Journal articles on the topic 'Burmah Oil Company'

Post-merger and Acquisition (M&A) integration often deals with significant transformational changes of merging companies in terms of development, communication, implementation and harmonization of a new shared vision, strategic objective, corporate culture, and also combination of best companies’ value practices. The transformational change is accentuated on facilitating the role of developing and executing an effective post-M&A Integration to build change cohesively with the strategic management of M&A, and also in terms of removing barriers to the success of M&A transaction. The aims of this study are to give a clear and deep understanding on how to manage the soft factors issues that address in M&A process especially in the post-M&A integration process and also to elucidate the critical success factor of M&A process by instilling the best characteristics and the effectiveness level of leadership aspect in M&A. The methodology used in this research is descriptive qualitative research with a method or approach of a case study of Henkel’s Acquisition of The Dial Corporation in 2004. The acquisition of a USA company Dial by a German company Henkel evidenced that both companies were successful in M&A transaction and employed the effectiveness of multi-culture integration strategy. Another case study used in this research is British Petroleum (BP) and American Oil Company (Amoco) (also Atlantic Richield Company (ARCO) and Burmah Castrol) in 1998-2000. The case of BP Amoco showed that the monoculture integration strategy or cultural imposition can also lead to a value creation. Both case studies showed that successful integration requires leadership as a foundation to build a solid execution of post-M&A integration projects in how they planned, communicated and delivered the objectives of the projects.

Exploration of the eastern Arabian Platform in the 1930s and 1940s by Chevron and its legacy company Gulf Oil resulted in discovery of Kuwait's super-giant Burgan Field by Gulf Oil in 1938 and Saudi Arabia's super-giant Ghawar Field by California Arabian Standard Oil Company in 1948. Ghawar Field and Burgan Field are widely regarded as the first- and second-largest oil fields in the world, respectively. Gravity methods featured prominently in Gulf's and Chevron's subsurface explorations. Gravity mapping identified the Burgan structure and was important in delineating the Ghawar structural complex. Gravimetric technology continues to provide value for deep exploration in Chevron's Partitioned Zone concession in Saudi Arabia and Kuwait.

The Canning Basin in northern Western Australia is a large, relatively remote, mainly desert-covered Phanerozoic basin covering 595 000 sq km. Aborigines probably first entered the basin area 30-40 000 years ago, but the main European expeditions were not until the nineteenth and twentieth centuries. Geological exploration in the basin has been largely devoted to the discovery and exploitation of natural resources, primarily oil. Earliest geological traverses were conducted by geologists of the Geological Survey of Western Australia (GSWA). The accidental discovery of traces of oil in a water well in 1919 in the northern part of the basin diverted exploration to assessment of sediments and structures for petroleum potential. The earliest phase of oil exploration was a pioneering phase, concentrating on surface mapping and surface delineated structures as drilling sites, that was dominated by the Freney Kimberley Oil Company. West Australia Petroleum Ltd became the most active oil exploration company in the 1950s, 1960s and 1970s, using geophysics as an exploration tool in petroleum search in the basin. The late 1970s and 1980s saw an influx of companies and the application of diverse scientific approaches to the oil search. Persistence was rewarded in 1981 and 1982 with the discovery of the Blina and Sundown fields, small commercial oil accumulations. Commonwealth Government involvement in exploration was initially in the form of financial aid to exploring companies or commissioning specialist consultants for special studies. In the 1940s and 1950s and again in the 1970s the Bureau of Mineral Resources carried out basin-wide regional geological mapping in conjunction with the GSWA; onshore and offshore geophysical surveys were conducted until the 1970s. Exploration has revealed exploitable resources in the basin besides oil - diamonds, lead-zinc, coal, salt, phosphate, uranium, and heavy minerals. Only lead-zinc has present economic viability.

This paper examines corporate tax ratio of manufacturing sector in Indonesia. In this study, we use firm level data from Industry Survey of Central Bureau of Statistics. The result shows that in small and medium company percentage of foreign ownership is a significant determinant of tax ratio, whereas in big companies capital is a significant determinant of tax ratio. This study also find that there is negative relationship between profitability and tax ratio. This indicates that there is tax avoidance risk in manufacturing sector in Indonesia. Further examination shows that industry of coal and oil refining product and also repair and installation of machinery and equipment has the biggest risk of tax avoidance. Therefore we recommend subsectoral tax audit for to prove the findings of this study. Penelitian ini menganalisis tax ratio perusahaan pada sektor manufaktur di Indonesia. Dalam penelitian ini digunakan data mikro perusaahaan manufaktur yang bersumber dari Survei Industri Badan Pusat Statistik. Hasil analisis menunjukkan bahwa terdapat hubungan positif antara kepemilikan asing dan tax ratio pada perusahaan menengah dan kecil, hal ini berbeda dengan pada perusahaan besar dimana kapital merupakan faktor yang mempengaruhi tax ratio. Hasil analisis juga menunjukkan bahwa terdapat hubungan negatif antara profitabilitas dan tax ratio. Hal ini mengindikasikan bahwa terdapat resiko penghindaran pajak pada sektor manufaktur di Indonesia. Penelitian lebih lanjut mengungkapkan bahwa industri produk dari batu bara dan pengilangan minyak bumi serta usaha reparasi dan pemasangan mesin dan peralatan merupakan industri dengan resiko penghindaran pajak yang terbesar. Oleh karena itulah kami menyarankan agar dilakukan pemeriksaan pajak subsektoral untuk membuktikan temuan pada penelitian ini.

GOM Lease Sale Generates $121 Million in High Bids; Shell Offshore Takes Top Spot Regionwide US Gulf of Mexico (GOM) Lease Sale 256 generated $120,868,274 in high bids for 93 tracts in federal waters. The sale on 18 November featured 14,862 unleased blocks covering 121,875 square miles. With $27,877,809 spanning 21 high bids, Shell Offshore Inc. took the top spot among 23 competing companies. A total of $135,558,336 was offered in 105 bids. Among the majors, Shell, Equinor, BP, and Chevron submitted some of the highest bids. Each company claimed high bids of over $17 million, signaling the GOM remains a priority in their portfolios. Last year was a record year for American offshore oil production at 596.9 million bbl, or 15% of domestic oil production, and $5.7 billion in direct revenues to the government. Offshore oil and gas supported 275,000 total domestic jobs and $60 billion total economic contributions in the US. “The sustained presence of large deposits of hydrocarbons in these waters will continue to draw the interest of industry for decades to come,” Deputy Secretary of the Interior Kate MacGregor said. Still, as Mfon Usoro, senior research analyst at Wood Mackenzie, noted, “Although bidding activity increased by 30% from the March 2020 sale, the high bid amount of $121 million still trends below the average high bid amount seen in previous regionwide lease sales, proving that companies are still being conservative with exploration spend.” Although the Bureau of Ocean Energy Management has proposed another regionwide GOM lease sale in March 2021, Usoro predicted that Lease Sale 256 “could potentially be one of the last lease sales.” “With the Biden administration set to inaugurate next year and possibly ban future lease sales, a massive land grab might have ensued,” he continued. “But companies are constrained by tight budgets due to the prevailing low oil price. Additionally, companies in the region have existing drilling inventory to sustain them in the near term. The best blocks with the highest potential reserves are likely already leased. As a result, we do not expect a potential ban on leasing to materially impact production in the region until the end of the decade.” This was the seventh offshore sale held under the 2017–2022 National Outer Continental Shelf Oil and Gas Leasing Program; two sales a year for 10 total regionwide lease sales are scheduled for the gulf. Nine Areas on Norwegian Continental Shelf Open for Bids The 25th licensing round on the Norwegian Continental Shelf, comprising eight areas in the Barents Sea and one in the Norwegian Sea, has been announced by the Norwegian Ministry of Petroleum and Energy. Known for being a country with some of the greenest credentials and policies in the world, Norway surprised observers in June by announcing plans for a licensing round that signaled further oil exploration in the Norwegian sector of the Arctic Sea. In this round, 136 blocks/parts of blocks will be available: 11 in the Norwegian Sea and 125 in the Barents Sea. The application deadline for companies is 23 February 2021. New production licenses will be awarded in Q2 2021. Johan Sverdrup Capacity Increased to Half Million B/D Following positive results in a November capacity test, the Johan Sverdrup field is set to increase daily production capacity. Capacity will rise from today’s 470,000 to around 500,000 B/D in the second increase since the field came on stream just over a year ago. The move will increase the field’s total production capacity by around 60,000 bbl more than the original basis when the field came on line. Overall, the field is estimated to have resources of 2.7 billion BOE. “The field has low operating costs, providing revenue for the companies and Norwegian society, even in periods with low prices,” said Jez Averty, Equinor’s senior vice president for operations south in development and production, Norway. The Johan Sverdrup field uses water injection to secure high recovery of reserves and maintain production at a high level. An increase in the water-injection capacity should further increase production capacity by mid-2021, according to Rune Nedregaard, vice president for Johan Sverdrup operations. Phase 2 production starting in Q4 2022 will raise the Johan Sverdrup full-field plateau production capacity from 690,000 to around 720,000 B/D. Equinor operates the field with 42.6% stake; other partners include Lundin Norway (20%), Petoro (17.36%), Aker BP (11.57%), and Total (8.44%). ConocoPhillips Makes Significant Gas Discovery Offshore Norway ConocoPhillips announced a new natural-gas condensate discovery in production license 1009, located 22 miles northwest of the Heidrun oil and gas field and 150 miles offshore Norway in the Norwegian Sea. The wildcat well 6507/4-1 (Warka) was drilled in 1,312 ft of water to a total depth of 16,355 ft. Preliminary estimates place the size of the discovery between 50 and 190 million BOE. Further appraisals will determine potential flow rates, the reservoir’s ultimate resource recovery, and plans for development. “The Warka discovery and potential future opportunities represent very low cost-of-supply resource additions that can extend our multi-decade success on the Norwegian Continental Shelf,” said Matt Fox, executive vice president and chief operating officer. The drilling operation, which was permitted to ConocoPhillips in August 2020, was performed by the Transocean-managed Leiv Eiriksson semisubmersible rig. ConocoPhillips Skandinavia AS is the main operator of the license with a 65% working interest; PGNiG Upstream Norway AS holds the remaining stake. Lundin Energy Completes Barents Sea Exploration Well, Comes Up Dry Lundin Energy has completed exploration well 7221/4-1, targeting the Polmak prospect in licenses PL609 and PL1027, in the southern Barents Sea. The well was meant to prove hydrocarbons in Triassic-aged sandstones within the Kobbe formation of the Polmak prospect. After finding indications of hydrocarbons in a 9-m interval in poor-quality reservoir in the targeted formation, the well was classified as dry. The well was drilled 30 km east of the Johan Castberg discovery, by the Seadrill-operated West Bollsta semisubmersible rig. Lundin Energy, operator of Polmak, holds a 47.51% working interest. Partners are Wintershall DEA Norge AS (25%), Inpex Norge AS (10%), DNO Norge AS (10%), and Idemitsu Petroleum Norge AS (7.5%). Polmak is the first of Lundin’s three high-impact exploration prospects drilled this quarter in the Barents Sea; the wells target gross unrisked prospective resources of over 800 million bbl of oil. The West Bollsta rig will now proceed to drill the Lundin Energy-operated Bask prospect in PL533B. Well 7219/11-1 will target Paleocene-aged sandstones, estimated to hold gross unrisked prospective resources of 250 million bbl of oil. Tullow Sells Remaining Stake in Ugandan Oil Field Tullow Oil has completed the 10 November sale of its assets in Uganda to French giant Total for $500 million. Tullow will also receive $75 million when a final investment decision is taken on the development project, calculated to hold 1.7 billion bbl of crude oil. Contingent payments are payable after production begins if Brent crude prices rise above $62/bbl. The completion of this transaction marks Tullow’s exit from its licenses in Uganda after 16 years of operations in the Lake Albert basin. The deal is designed to strengthen Tullow’s balance sheet, as tumbling crude prices combined with exploration setbacks have created problems for the company. In September, the company reported that it had lost $1.3 billion in the first 6 months of 2020 as falling oil prices forced it to write down the value of its assets. The deal cut Tullow’s net debt to $2.4 billion; it has $1 billion in cash.

Background:Nailfold capillaroscopy (NVC), a non-invasive technique to assess microcirculation, is increasingly being incorporated into rheumatology routine clinical practice. Currently, the degree of description of NVC methods varies amongst research studies, making interpretation and comparison between studies challenging. In this field, an unmet need is the standardization of items to be reported in research studies using NVC.Objectives:To perform a Delphi consensus on minimum reporting standards in methodology for clinical research, based on the items derived from a systematic review focused on this topic.Methods:The systematic review of the literature on NVC methodology relating to rheumatic diseases was performed according to PRISMA guidelines (PROSPERO CRD42018104660) to July 22nd2018 using MEDLINE, Embase, Scopus. Then, a three-step web-based Delphi consensus was performed in between members of the EULAR study group on microcirculation in rheumatic diseases and the Scleroderma Clinical Trials Consortium. Participants were asked to rate each item from 1 (not appropriate) to 9 (completely appropriate).Results:In total, 3491 references were retrieved in the initial search strategy, 2862 were excluded as duplicates or after title/abstract screening. 632 articles were retrieved for full paper review of which 319 fulfilled the inclusion criteria. Regarding patient preparation before the exam, data were scarce: 38% reported acclimatization, 5% to avoid caffeine and smoking, 3% to wash hands and 2% to avoid manicure. Concerning the device description: 90% reported type of instrument, 77% brand/model, 72% magnification, 46% oil use, 40% room temperature and 35% software for image analysis. As regards to examination details: 76% which fingers examined, 75% number of fingers examined, 15% operator experience, 13% reason for finger exclusion, 9% number of images, 8% quality check of the images and 3% time spent for the exam. Then, a three-round Delphi consensus on the selected items was completed by 80 participants internationally, from 31 countries located in Australia, Asia, Europe, North and South America. Some items reached the agreement at the second round (85 participants), and other items were suggested as important to consider in a future research agenda (e.g. temperature for acclimatization, the impact of smoking, allergies at the application of the oil to the nailbed, significance of pericapillary edema, methods of reporting hemorrhages, ramified and giant capillaries). The final agreement results are reported below:Conclusion:On the basis of the available literature the description of NVC methods was highly heterogeneous and individual published studies differed markedly. These practical suggestions developed using a Delphi process among international participants provide a guidance to improve and to standardize the NVC methodology in future clinical research studies.Disclosure of Interests:Francesca Ingegnoli: None declared, Tommaso Schioppo: None declared, Ariane Herrick: None declared, Alberto Sulli Grant/research support from: Laboratori Baldacci, Francesca Bartoli: None declared, Nicola Ughi: None declared, John Pauling: None declared, Maurizio Cutolo Grant/research support from: Bristol-Myers Squibb, Actelion, Celgene, Consultant of: Bristol-Myers Squibb, Speakers bureau: Sigma-Alpha, Vanessa Smith Grant/research support from: The affiliated company received grants from Research Foundation - Flanders (FWO), Belgian Fund for Scientific Research in Rheumatic diseases (FWRO), Boehringer Ingelheim Pharma GmbH & Co and Janssen-Cilag NV, Consultant of: Boehringer-Ingelheim Pharma GmbH & Co, Speakers bureau: Actelion Pharmaceuticals Ltd, Boehringer-Ingelheim Pharma GmbH & Co and UCB Biopharma Sprl

The privatisation and commercialisation Decree No. 25 of 1988 (amended 1999) which provided the legal backing for the Technical Committee of Privatisation and Commercialisation (TCPC), began the major paradigm shift in the conceptualisation of public enterprises in Nigeria. The paper primarily examined the privatisation exercise in Nigeria since 1988. It also attempted to provide measures that will simplify the complex process of privatisation with the hope of lessening the probability of crisis. The paper considered the impact of privatisation on performance of privatised companies, changes in employment and the increase in the prices of commodities of the enterprises vis-à-vis their gross income towards the overall good governance of the Nigerian society.The data for the paper were mainly secondary; and were drawn from the financial statements of companies in the stock Exchange and other stock Exchange reports, Central Bank Bulletins, publications and published reports of the Bureau of Public Enterprises. Newspapers and publication of the Federal Office of Statistics are other sources. The data were analysed by trend analysis using absolute figures, percentages and ratios based on the past record on privatisation in Nigeria.However, the study discovered that only a few successful enterprises, Flour Mills, African Petroleum, National oil and Chemical Marketing Company Limited (NOLCHEM) were partially privatised. The commercialisation of enterprises such as National Electric Power Authority (NEPA), Nigeria Telecommunications (NITEL) and Nigerian National Petroleum Corporation (NNPC), hardly showed any significant improvement in their operational and economic performance.The papers showed that employment levels were affected by privatisation. Between 1989 and 1993, the public sector accounted for more job losses than privatised companies. When privatised firms employment rose, public and private sectors still had lower employment levels. The sharp increase in prices between 1992 and 1994 did not create a sufficient increase in gross earnings for 1994. The results revealed that a reduction in public control would have an effect (at least in the short term) on prices. Profits increase but the extent to which this increase can attributed to reduction of government controls is not clear. Three banks witnessed sharp increase in investments and profitability immediately after privatisation, and there was a slight decrease before another increase. Results showed that privatisation has improved company performance, especially in the efficiency of resources utilisation. Higher profit to capital employed ratios has been witnessed since privatisation. Debt/Total Asset ratios have not been affected in any adverse way. Results from the study also revealed that price increases in excess of 200% occurred immediately after privatisation. This perhaps has an effect on the profits of the companies (especially those that still maintained monopoly status for a while.However, one fact is clear: the heydays of public enterprises in Nigeria are gone for good. It was on this note that the study concluded that privatisation is the appropriate economic recipe to achieve the much desired human development and good governance.

Summary Rock-compaction drive under waterflood re-pressurization has not been accounted for previously in our flow-model studies for a Valhall waterflood. However, field observations from pilot waterfloods indicate an increase in permeability with the injection of cool seawater into the chalk formation. Platform subsidence measurements taken during the pilot waterflood also provide evidence of a chalk/water interaction. Laboratory experiments on reservoir core samples indicate an accelerated compaction effect as the flood front passes through the sample. To assess the value of a large-scale waterflood at Valhall, we have developed a new approach to simulate the possible effects of water-induced rock compaction in our black-oil flow models. Introduction Rock-compaction drive induced by pressure decline is estimated to contribute 50% of the oil recovery from the Valhall Cretaceous Age chalk reservoir under primary depletion.1 The tremendous natural energy coming from pressure-induced rock-compaction drive has led to a delay in waterflood plans at Valhall. However, as reported by Andersen et al.,2 laboratory tests on Valhall cores indicate vertical compaction caused by the introduction of water under constant stress conditions. Piau and Maury3 relate the disciplines of soil mechanics and petroleum engineering relative to the weakening/induced compaction effects of water on chalk. Further, as reported by Chin and Prevost,4 the weakening effect of water on chalk compaction may make waterflooding more economically favorable for improving oil recovery from some North Sea chalk reservoirs. Water-Induced Rock Compaction Compaction drive from pressure depletion significantly contributes to oil recoveries in both the Valhall and Ekofisk fields.1,5 It was previously believed that the mechanism to invoke compaction was exclusively related to pressure depletion. However, field and laboratory experience point to the fact that compaction may also occur from chalk/water interaction, even at constant stress. We no longer believe that reservoir-pressure maintenance with water injection will arrest compaction. The question now is whether water weakening only accelerates compaction or increases ultimate compaction.4 A Physical Picture. Fig. 1schematically illustrates in simple terms the Valhall chalk reservoir in the form of a cube in its initial state, followed by primary depletion and then waterflood. Primary Depletion. Under primary depletion, the chalk cube's temperature remains constant while its pressure is lowered (see Fig. 1). Plastic deformation occurs, which at Valhall is believed to be caused by pore collapse. The chalk cube shrinks and the natural fractures heal (i.e., permeability reduction). Waterflood. The chalk cube is then injected with cool seawater, whereby its temperature is lowered and pressure is increased. According to Perkins and Gonzalez6 and Teufel and Rhett,7 the stress state of the core is altered so that the average effective stress decreases while maintaining a constant shear stress(i.e., weight of the overburden). The decreased stress state may be compared to a loss of strength. Again, Fig. 1 shows that the waterflood result is a further collapse of the chalk cube. However, permeability is slightly increased owing to induced fracturing. Physics. As reported by Maury et al.,8 typical chalks from Valhall field are very pure, made up of 98 to 100% calcium carbonate, without any secondary minerals. When a waterflood passes through this type of chalk it can generate compaction. The compaction is localized to the flood front, but decays slowly with time after the front passes. The effect is greater if the chalk is in a plastic state. We do not know the microscopic physical mechanism associated with the compaction, but it is believed to be associated with capillary pressure effects. The increased water saturation disturbs the capillary forces, destabilizing the chalk and causing it to compact. The additional deformation induced by water saturation has been described in a constitutive theoretical analysis of chalk.8 Fractures. As described by Andersen9 and illustrated in Fig. 2, when the flood front passes through, the chalk may compact and fracture. Perkins and Gonzalez10 describe the similar cool-water fracturing as secondary fractures resulting from changes in the in-situ stress. Teufel and Rhett7 report large increases in reservoir permeability measured in well tests conducted before and after waterflooding, indicating the extensive nature of waterflood-induced fracturing at Ekofisk. Hydraulic Fractures. The fractures resulting from water-induced compaction are distinct from the hydraulic fractures created as a result of injecting above formation parting pressure. Both types of fracturing significantly contribute to flow conductivity, but hydraulic fractures are confined to the injection well areas and are believed to open and close based on bottomhole injection pressure. Thermal Effects. Charlez et al.11 explain the two main offsetting effects of cooling on the mechanical behavior of chalk during water injection. The first effect is a stiffening or strengthening of the material with decreasing temperature. The second effect is thermal contraction of both the solid and the fluid, which induces thermal stresses. The overall thermal waterflood effect on the mechanical behavior of North Sea chalk is not conclusively determined and warrants further investigation. Valhall Field The Valhall field is located within the North Sea Central graben consisting of late Cretaceous Age rock. The field structure is an asymmetrical dome with a relatively steep western flank resulting from basin inversion along a regional fault system known as the Lindesnes fault. Reservoir depth is 2400 m subsea with a free water level at 2630 m subsea. Initial reservoir temperature and pressure were 195°F and 6600 psia, respectively. The reservoir consists of two formations, the Tor and Hod. Initial rock porosities in the Tor generally range from 40 to 50%; porosities in the Hod formation are lower, ranging from 25 to 40%. The main reason for the preservation of such high porosity is believed to be the early migration of oil into the coccolith pore space before significant burial. One might say that over the years the oil has acted as an embalming fluid, protecting the chalk body from porosity decay.

In recent years, there has been a growing interest in finding early predictors of Parkinson’s disease. In this regard, it is worth noting the olfactory dysfunction, which is associated with the death of neurons in the structures of the limbic system of the brain and a decrease in dopamine levels in the striatum. It was found that most patients with Parkinson’s disease have a clear olfactory dysfunction in the form of impaired differentiation and identification of odors. It has been suggested that the use of low doses of dopamine in the early stages of Parkinson’s disease will stop the progression of central nervous system disorders. The purpose of the study was to investigate the effect of intranasal administration of small doses of dopamine on the early manifestations of fine motor skills and olfactory sensory system function in nigrostriatal dysfunction in rats. Materials and methods. The experiments were performed on 2 groups of animals (n=14) with nigrostriatal dysfunction, which was modulated by partial bilateral electrical damage to the compact part of the substantia nigra. Stereotactic coordinates of the substantia nigra area were determined from the brain maps of rats by Fifkova and Marshall (quoted by Buresh), which corresponded to the distance from the point of intersection of the sagittal suture with bregma: F=5.5 mm, L=1.7 mm, H=9.0 mm. Rats of the first group (n=8) were intranasally administered with small doses of dopamine, and rats of the second group (n=6) were a comparison group. The fine motor skills of the forelimbs and the functional state of the olfactory system were studied when rats were presented with different odorants: emotionally positive (isovaleric acid) and emotionally negative (lemon essential oil) odorants. Results and discussion. The dynamics of the development of nigrostriatal dysfunction revealed a decrease in coordinated motor activity of the forelimbs, muscles of the oral pole and tongue and increased olfactory sensitivity to emotionally negative odorant (lemon essential oil) and loss of 40% of animals’ olfactory sensitivity to emotionally positive isovaleric odor. Conclusion. Prolonged intranasal administration of low doses of dopamine for 10 days to rats with nigrostriatal dysfunction resulted in a 26.2% increase in the activity of fine motor skills of the forelimbs, oral poles and tongue. In these rats, recovery of olfactory sensitivity to the perception of the smell of emotionally negative odorant was found. The action of the emotionally positive stimulus of isovaleric acid revealed an increase in olfactory sensitivity in 75% of animals to the level of baseline values and a decrease in the threshold of sensitivity to it, which was reflected in an increase in the number of approaches and time of odorant research

Environments containing significant concentration of NaCl such as salt lakes harbor extremophiles microorganisms which have a great biotechnology interest. To explore the diversity of Bacteria in Chott Tinsilt (Algeria), an isolation program was performed. Water samples were collected from the saltern during the pre-salt harvesting phase. This Chott is high in salt (22.47% (w/v). Seven halophiles Bacteria were selected for further characterization. The isolated strains were able to grow optimally in media with 10–25% (w/v) total salts. Molecular identification of the isolates was performed by sequencing the 16S rRNA gene. It showed that these cultured isolates included members belonging to the Halomonas, Staphylococcus, Salinivibrio, Planococcus and Halobacillus genera with less than 98% of similarity with their closest phylogenetic relative. The halophilic bacterial isolates were also characterized for the production of biosurfactant and industrially important enzymes. Most isolates produced hydrolases and biosurfactants at high salt concentration. In fact, this is the first report on bacterial strains (A4 and B4) which were a good biosurfactant and coagulase producer at 20% and 25% ((w/v)) NaCl. In addition, the biosurfactant produced by the strain B4 at high salinity (25%) was also stable at high temperature (30-100°C) and high alkalinity (pH 11).Key word: Salt Lake, Bacteria, biosurfactant, Chott, halophiles, hydrolases, 16S rRNAINTRODUCTIONSaline lakes cover approximately 10% of the Earth’s surface area. The microbial populations of many hypersaline environments have already been studied in different geographical regions such as Great Salt Lake (USA), Dead Sea (Israel), Wadi Natrun Lake (Egypt), Lake Magadi (Kenya), Soda Lake (Antarctica) and Big Soda Lake and Mono Lake (California). Hypersaline regions differ from each other in terms of geographical location, salt concentration and chemical composition, which determine the nature of inhabitant microorganisms (Gupta et al., 2015). Then low taxonomic diversity is common to all these saline environments (Oren et al., 1993). Halophiles are found in nearly all major microbial clades, including prokaryotic (Bacteria and Archaea) and eukaryotic forms (DasSarma and Arora, 2001). They are classified as slight halophiles when they grow optimally at 0.2–0.85 M (2–5%) NaCl, as moderate halophiles when they grow at 0.85–3.4 M (5–20%) NaCl, and as extreme halophiles when they grow at 3.4–5.1 M (20–30%) NaCl. Hyper saline environments are inhabited by extremely halophilic and halotolerant microorganisms such as Halobacillus sp, Halobacterium sp., Haloarcula sp., Salinibacter ruber , Haloferax sp and Bacillus spp. (Solomon and Viswalingam, 2013). There is a tremendous demand for halophilic bacteria due to their biotechnological importance as sources of halophilic enzymes. Enzymes derived from halophiles are endowed with unique structural features and catalytic power to sustain the metabolic and physiological processes under high salt conditions. Some of these enzymes have been reported to be active and stable under more than one extreme condition (Karan and Khare, 2010). Applications are being considered in a range of industries such as food processing, washing, biosynthetic processes and environmental bioremediation. Halophilic proteases are widely used in the detergent and food industries (DasSarma and Arora, 2001). However, esterases and lipases have also been useful in laundry detergents for the removal of oil stains and are widely used as biocatalysts because of their ability to produce pure compounds. Likewise, amylases are used industrially in the first step of the production of high fructose corn syrup (hydrolysis of corn starch). They are also used in the textile industry in the de-sizing process and added to laundry detergents. Furthermore, for the environmental applications, the use of halophiles for bioremediation and biodegradation of various materials from industrial effluents to soil contaminants and accidental spills are being widely explored. In addition to enzymes, halophilic / halotolerants microorganisms living in saline environments, offer another potential applications in various fields of biotechnology like the production of biosurfactant. Biosurfactants are amphiphilic compounds synthesized from plants and microorganisms. They reduce surface tension and interfacial tension between individual molecules at the surface and interface respectively (Akbari et al., 2018). Comparing to the chemical surfactant, biosurfactant are promising alternative molecules due to their low toxicity, high biodegradability, environmental capability, mild production conditions, lower critical micelle concentration, higher selectivity, availability of resources and ability to function in wide ranges of pH, temperature and salinity (Rocha et al., 1992). They are used in various industries which include pharmaceuticals, petroleum, food, detergents, cosmetics, paints, paper products and water treatment (Akbari et al., 2018). The search for biosurfactants in extremophiles is particularly promising since these biomolecules can adapt and be stable in the harsh environments in which they are to be applied in biotechnology.OBJECTIVESEastern Algeria features numerous ecosystems including hypersaline environments, which are an important source of salt for food. The microbial diversity in Chott Tinsilt, a shallow Salt Lake with more than 200g/L salt concentration and a superficies of 2.154 Ha, has never yet been studied. The purpose of this research was to chemically analyse water samples collected from the Chott, isolate novel extremely or moderate halophilic Bacteria, and examine their phenotypic and phylogenetic characteristics with a view to screening for biosurfactants and enzymes of industrial interest.MATERIALS AND METHODSStudy area: The area is at 5 km of the Commune of Souk-Naâmane and 17 km in the South of the town of Aïn-Melila. This area skirts the trunk road 3 serving Constantine and Batna and the railway Constantine-Biskra. It is part the administrative jurisdiction of the Wilaya of Oum El Bouaghi. The Chott belongs to the wetlands of the High Plains of Constantine with a depth varying rather regularly without never exceeding 0.5 meter. Its length extends on 4 km with a width of 2.5 km (figure 1).Water samples and physico-chemical analysis: In February 2013, water samples were collected from various places at the Chott Tinsilt using Global Positioning System (GPS) coordinates of 35°53’14” N lat. and 06°28’44”E long. Samples were collected randomly in sterile polythene bags and transported immediately to the laboratory for isolation of halophilic microorganisms. All samples were treated within 24 h after collection. Temperature, pH and salinity were measured in situ using a multi-parameter probe (Hanna Instruments, Smithfield, RI, USA). The analytical methods used in this study to measure ions concentration (Ca2+, Mg2+, Fe2+, Na+, K+, Cl−, HCO3−, SO42−) were based on 4500-S-2 F standard methods described elsewhere (Association et al., 1920).Isolation of halophilic bacteria from water sample: The media (M1) used in the present study contain (g/L): 2.0 g of KCl, 100.0/200.0 g of NaCl, 1.0 g of MgSO4.7HO2, 3.0 g of Sodium Citrate, 0.36 g of MnCl2, 10.0 g of yeast extract and 15.0 g agar. The pH was adjusted to 8.0. Different dilutions of water samples were added to the above medium and incubated at 30°C during 2–7 days or more depending on growth. Appearance and growth of halophilic bacteria were monitored regularly. The growth was diluted 10 times and plated on complete medium agar (g/L): glucose 10.0; peptone 5.0; yeast extract 5.0; KH2PO4 5.0; agar 30.0; and NaCl 100.0/200.0. Resultant colonies were purified by repeated streaking on complete media agar. The pure cultures were preserved in 20% glycerol vials and stored at −80°C for long-term preservation.Biochemical characterisation of halophilic bacterial isolates: Bacterial isolates were studied for Gram’s reaction, cell morphology and pigmentation. Enzymatic assays (catalase, oxidase, nitrate reductase and urease), and assays for fermentation of lactose and mannitol were done as described by Smibert (1994).Optimization of growth conditions: Temperature, pH, and salt concentration were optimized for the growth of halophilic bacterial isolates. These growth parameters were studied quantitatively by growing the bacterial isolates in M1 medium with shaking at 200 rpm and measuring the cell density at 600 nm after 8 days of incubation. To study the effect of NaCl on the growth, bacterial isolates were inoculated on M1 medium supplemented with different concentration of NaCl: 1%-35% (w/v). The effect of pH on the growth of halophilic bacterial strains was studied by inoculating isolates on above described growth media containing NaCl and adjusted to acidic pH of 5 and 6 by using 1N HCl and alkaline pH of 8, 9, 10, 11 and 12 using 5N NaOH. The effect of temperature was studied by culturing the bacterial isolates in M1 medium at different temperatures of incubation (4°C–55°C).Screening of halophilic bacteria for hydrolytic enzymes: Hydrolase producing bacteria among the isolates were screened by plate assay on starch, tributyrin, gelatin and DNA agar plates respectively for amylase, lipase, protease and DNAse activities. Amylolytic activity of the cultures was screened on starch nutrient agar plates containing g/L: starch 10.0; peptone 5.0; yeast extract 3.0; agar 30.0; NaCl 100.0/250.0. The pH was 7.0. After incubation at 30 ºC for 7 days, the zone of clearance was determined by flooding the plates with iodine solution. The potential amylase producers were selected based on ratio of zone of clearance diameter to colony diameter. Lipase activity of the cultures was screened on tributyrin nutrient agar plates containing 1% (v/v) of tributyrin. Isolates that showed clear zones of tributyrin hydrolysis were identified as lipase producing bacteria. Proteolytic activity of the isolates was similarly screened on gelatin nutrient agar plates containing 10.0 g/L of gelatin. The isolates showing zones of gelatin clearance upon treatment with acidic mercuric chloride were selected and designated as protease producing bacteria. The presence of DNAse activity on plates was determined on DNAse test agar (BBL) containing 10%-25% (w/v) total salt. After incubation for 7days, the plates were flooded with 1N HCl solution. Clear halos around the colonies indicated DNAse activity (Jeffries et al., 1957).Milk clotting activity (coagulase activity) of the isolates was also determined following the procedure described (Berridge, 1952). Skim milk powder was reconstituted in 10 mM aqueous CaCl2 (pH 6.5) to a final concentration of 0.12 kg/L. Enzyme extracts were added at a rate of 0.1 mL per mL of milk. The coagulation point was determined by manual rotating of the test tube periodically, at short time intervals, and checking for visible clot formation.Screening of halophilic bacteria for biosurfactant production. Oil spread Assay: The Petridis base was filled with 50 mL of distilled water. On the water surface, 20μL of diesel and 10μl of culture were added respectively. The culture was introduced at different spots on the diesel, which is coated on the water surface. The occurrence of a clear zone was an indicator of positive result (Morikawa et al., 2000). The diameter of the oil expelling circles was measured by slide caliber (with a degree of accuracy of 0.02 mm).Surface tension and emulsification index (E24): Isolates were cultivated at 30 °C for 7 days on the enrichment medium containing 10-25% NaCl and diesel oil as the sole carbon source. The medium was centrifuged (7000 rpm for 20 min) and the surface tension of the cell-free culture broth was measured with a TS90000 surface tensiometer (Nima, Coventry, England) as a qualitative indicator of biosurfactant production. The culture broth was collected with a Pasteur pipette to remove the non-emulsified hydrocarbons. The emulsifying capacity was evaluated by an emulsification index (E24). The E24 of culture samples was determined by adding 2 mL of diesel oil to the same amount of culture, mixed for 2 min with a vortex, and allowed to stand for 24 h. E24 index is defined as the percentage of height of emulsified layer (mm) divided by the total height of the liquid column (mm).Biosurfactant stability studies : After growth on diesel oil as sole source of carbone, cultures supernatant obtained after centrifugation at 6,000 rpm for 15 min were considered as the source of crude biosurfactant. Its stability was determined by subjecting the culture supernatant to various temperature ranges (30, 40, 50, 60, 70, 80 and 100 °C) for 30 min then cooled to room temperature. Similarly, the effect of different pH (2–11) on the activity of the biosurfactant was tested. The activity of the biosurfactant was investigated by measuring the emulsification index (El-Sersy, 2012).Molecular identification of potential strains. DNA extraction and PCR amplification of 16S rDNA: Total cellular DNA was extracted from strains and purified as described by Sambrook et al. (1989). DNA was purified using Geneclean® Turbo (Q-BIO gene, Carlsbad, CA, USA) before use as a template in polymerase chain reaction (PCR) amplification. For the 16S rDNA gene sequence, the purified DNA was amplified using a universal primer set, forward primer (27f; 5′-AGA GTT TGA TCM TGG CTC AG) and a reverse primer (1492r; 5′-TAC GGY TAC CTT GTT ACG ACT T) (Lane, 1991). Agarose gel electrophoresis confirmed the amplification product as a 1400-bp DNA fragment.16S rDNA sequencing and Phylogenic analysis: Amplicons generated using primer pair 27f-1492r was sequenced using an automatic sequencer system at Macrogene Company (Seoul, Korea). The sequences were compared with those of the NCBI BLAST GenBank nucleotide sequence databases. Phylogenetic trees were constructed by the neighbor-joining method using MEGA version 5.05 software (Tamura et al., 2011). Bootstrap resembling analysis for 1,000 replicates was performed to estimate the confidence of tree topologies.Nucleotide sequence accession numbers: The nucleotide sequences reported in this work have been deposited in the EMBL Nucleotide Sequence Database. The accession numbers are represented in table 5.Statistics: All experiments were conducted in triplicates. Results were evaluated for statistical significance using ANOVA.RESULTSPhysico-chemical parameters of the collected water samples: The physicochemical properties of the collected water samples are reported in table 1. At the time of sampling, the temperature was 10.6°C and pH 7.89. The salinity of the sample, as determined in situ, was 224.70 g/L (22,47% (w/v)). Chemical analysis of water sample indicated that Na +and Cl- were the most abundant ions (table 1). SO4-2 and Mg+2 was present in much smaller amounts compared to Na +and Cl- concentration. Low levels of calcium, potassium and bicarbonate were also detected, often at less than 1 g/L.Characterization of isolates. Morphological and biochemical characteristic feature of halophilic bacterial isolates: Among 52 strains isolated from water of Chott Tinsilt, seven distinct bacteria (A1, A2, A3, A4, B1, B4 and B5) were chosen for further characterization (table 2). The colour of the isolates varied from beige, pale yellow, yellowish and orange. The bacterial isolates A1, A2, A4, B1 and B5 were rod shaped and gram negative (except B5), whereas A3 and B4 were cocci and gram positive. All strains were oxidase and catalase positive except for B1. Nitrate reductase and urease activities were observed in all the bacterial isolates, except B4. All the bacterial isolates were negative for H2S formation. B5 was the only strain positive for mannitol fermentation (table 2).We isolated halophilic bacteria on growth medium with NaCl supplementation at pH 7 and temperature of 30°C. We studied the effect of NaCl, temperature and pH on the growth of bacterial isolates. All the isolates exhibited growth only in the presence of NaCl indicating that these strains are halophilic. The optimum growth of isolates A3 and B1 was observed in the presence of 10% NaCl, whereas it was 15% NaCl for A1, A2 and B5. A4 and B4 showed optimum growth in the presence of 20% and 25% NaCl respectively. A4, B4 and B5 strains can tolerate up to 35% NaCl.The isolate B1 showed growth in medium supplemented with 10% NaCl and pH range of 7–10. The optimum pH for the growth B1 was 9 and they did not show any detectable growth at or below pH 6 (table 2), which indicates the alkaliphilic nature of B1 isolate. The bacterial isolates A1, A2 and A4 exhibited growth in the range of pH 6–10, while A3 and B4 did not show any growth at pH greater than 8. The optimum pH for growth of all strains (except B1) was pH 7.0 (table 2). These results indicate that A1, A2, A3, A4, B4 and B5 are neutrophilic in nature. All the bacterial isolates exhibited optimal growth at 30°C and no detectable growth at 55°C. Also, detectable growth of isolates A1, A2 and A4 was observed at 4°C. However, none of the bacterial strains could grow below 4°C and above 50°C (table 2).Screening of the halophilic enzymes: To characterize the diversity of halophiles able to produce hydrolytic enzymes among the population of microorganisms inhabiting the hypersaline habitats of East Algeria (Chott Tinsilt), a screening was performed. As described in Materials and Methods, samples were plated on solid media containing 10%-25% (w/v) of total salts and different substrates for the detection of amylase, protease, lipase and DNAse activities. However, coagulase activity was determined in liquid medium using milk as substrate (figure 3). Distributions of hydrolytic activity among the isolates are summarized in table 4.From the seven bacterial isolates, four strains A1, A2, A4 and B5 showed combined hydrolytic activities. They were positive for gelatinase, lipase and coagulase. A3 strain showed gelatinase and lipase activities. DNAse activities were detected with A1, A4, B1 and B5 isolates. B4 presented lipase and coagulase activity. Surprisingly, no amylase activity was detected among all the isolates.Screening for biosurfactant producing isolates: Oil spread assay: The results showed that all the strains could produce notable (>4 cm diameter) oil expelling circles (ranging from 4.11 cm to 4.67 cm). The average diameter for strain B5 was 4.67 cm, significantly (P < 0.05) higher than for the other strains.Surface tension and emulsification index (E24): The assimilation of hydrocarbons as the sole sources of carbon by the isolate strains led to the production of biosurfactants indicated by the emulsification index and the lowering of the surface tension of cell-free supernatant. Based on rapid growth on media containing diesel oil as sole carbon source, the seven isolates were tested for biosurfactant production and emulsification activity. The obtained values of the surface tension measurements as well as the emulsification index (E24) are shown in table 3. The highest reduction of surface tension was achieved with B5 and A3 isolates with values of 25.3 mN m−1 and 28.1 mN m−1 respectively. The emulsifying capacity evaluated by the E24 emulsification index was highest in the culture of isolate B4 (78%), B5 (77%) and A3 (76%) as shown in table 3 and figure 2. These emulsions were stable even after 4 months. The bacteria with emulsification indices higher than 50 % and/or reduction in the surface tension (under 30 mN/m) have been defined as potential biosurfactant producers. Based on surface tension and the E24 index results, isolates B5, B4, A3 and A4 are the best candidates for biosurfactant production. It is important to note that, strains B4 and A4 produce biosurfactant in medium containing respectively 25% and 20% (w/v) NaCl.Stability of biosurfactant activities: The applicability of biosurfactants in several biotechnological fields depends on their stability at different environmental conditions (temperatures, pH and NaCl). For this study, the strain B4 appear very interesting (It can produce biosurfactant at 25 % NaCl) and was choosen for futher analysis for biosurfactant stability. The effects of temperature and pH on the biosurfactant production by the strain B4 are shown in figure 4.biosurfactant in medium containing respectively 25% and 20% (w/v) NaCl.Stability of biosurfactant activities: The applicability of biosurfactants in several biotechnological fields depends on their stability at different environmental conditions (temperatures, pH and NaCl). For this study, the strain B4 appear very interesting (It can produce biosurfactant at 25 % NaCl) and was chosen for further analysis for biosurfactant stability. The effects of temperature and pH on the biosurfactant production by the strain B4 are shown in figure 4. The biosurfactant produced by this strain was shown to be thermostable giving an E-24 Index value greater than 78% (figure 4A). Heating of the biosurfactant to 100 °C caused no significant effect on the biosurfactant performance. Therefore, the surface activity of the crude biosurfactant supernatant remained relatively stable to pH changes between pH 6 and 11. At pH 11, the value of E24 showed almost 76% activity, whereas below pH 6 the activity was decreased up to 40% (figure 4A). The decreases of the emulsification activity by decreasing the pH value from basic to an acidic region; may be due to partial precipitation of the biosurfactant. This result indicated that biosurfactant produced by strain B4 show higher stability at alkaline than in acidic conditions.Molecular identification and phylogenies of potential isolates: To identify halophilic bacterial isolates, the 16S rDNA gene was amplified using gene-specific primers. A PCR product of ≈ 1.3 kb was detected in all the seven isolates. The 16S rDNA amplicons of each bacterial isolate was sequenced on both strands using 27F and 1492R primers. The complete nucleotide sequence of 1336,1374, 1377,1313, 1305,1308 and 1273 bp sequences were obtained from A1, A2, A3, A4, B1, B4 and B5 isolates respectively, and subjected to BLAST analysis. The 16S rDNA sequence analysis showed that the isolated strains belong to the genera Halomonas, Staphylococcus, Salinivibrio, Planococcus and Halobacillus as shown in table 5. The halophilic isolates A2 and A4 showed 97% similarity with the Halomonas variabilis strain GSP3 (accession no. AY505527) and the Halomonas sp. M59 (accession no. AM229319), respectively. As for A1, it showed 96% similarity with the Halomonas venusta strain GSP24 (accession no. AY553074). B1 and B4 showed for their part 96% similarity with the Salinivibrio costicola subsp. alcaliphilus strain 18AG DSM4743 (accession no. NR_042255) and the Planococcus citreus (accession no. JX122551), respectively. The bacterial isolate B5 showed 98% sequence similarity with the Halobacillus trueperi (accession no. HG931926), As for A3, it showed only 95% similarity with the Staphylococcus arlettae (accession no. KR047785). The 16S rDNA nucleotide sequences of all the seven halophilic bacterial strains have been submitted to the NCBI GenBank database under the accession number presented in table 5. The phylogenetic association of the isolates is shown in figure 5.DICUSSIONThe physicochemical properties of the collected water samples indicated that this water was relatively neutral (pH 7.89) similar to the Dead Sea and the Great Salt Lake (USA) and in contrast to the more basic lakes such as Lake Wadi Natrun (Egypt) (pH 11) and El Golea Salt Lake (Algeria) (pH 9). The salinity of the sample was 224.70 g/L (22,47% (w/v). This range of salinity (20-30%) for Chott Tinsilt is comparable to a number of well characterized hypersaline ecosystems including both natural and man-made habitats, such as the Great Salt Lake (USA) and solar salterns of Puerto Rico. Thus, Chott Tinsilt is a hypersaline environment, i.e. environments with salt concentrations well above that of seawater. Chemical analysis of water sample indicated that Na +and Cl- were the most abundant ions, as in most hypersaline ecosystems (with some exceptions such as the Dead Sea). These chemical water characteristics were consistent with the previously reported data in other hypersaline ecosystems (DasSarma and Arora, 2001; Oren, 2002; Hacěne et al., 2004). Among 52 strains isolated from this Chott, seven distinct bacteria (A1, A2, A3, A4, B1, B4 and B5) were chosen for phenotypique, genotypique and phylogenetique characterization.The 16S rDNA sequence analysis showed that the isolated strains belong to the genera Halomonas, Staphylococcus, Salinivibrio, Planococcus and Halobacillus. Genera obtained in the present study are commonly occurring in various saline habitats across the globe. Staphylococci have the ability to grow in a wide range of salt concentrations (Graham and Wilkinson, 1992; Morikawa et al., 2009; Roohi et al., 2014). For example, in Pakistan, Staphylococcus strains were isolated from various salt samples during the study conducted by Roohi et al. (2014) and these results agreed with previous reports. Halomonas, halophilic and/or halotolerant Gram-negative bacteria are typically found in saline environments (Kim et al., 2013). The presence of Planococcus and Halobacillus has been reported in studies about hypersaline lakes; like La Sal del Rey (USA) (Phillips et al., 2012) and Great Salt Lake (Spring et al., 1996), respectively. The Salinivibrio costicola was a representative model for studies on osmoregulatory and other physiological mechanisms of moderately halophilic bacteria (Oren, 2006).However, it is interesting to note that all strains shared less than 98.7% identity (the usual species cut-off proposed by Yarza et al. (2014) with their closest phylogenetic relative, suggesting that they could be considered as new species. Phenotypic, genetic and phylogenetic analyses have been suggested for the complete identification of these strains. Theses bacterial strains were tested for the production of industrially important enzymes (Amylase, protease, lipase, DNAse and coagulase). These isolates are good candidates as sources of novel enzymes with biotechnological potential as they can be used in different industrial processes at high salt concentration (up to 25% NaCl for B4). Prominent amylase, lipase, protease and DNAase activities have been reported from different hypersaline environments across the globe; e.g., Spain (Sánchez‐Porro et al., 2003), Iran (Rohban et al., 2009), Tunisia (Baati et al., 2010) and India (Gupta et al., 2016). However, to the best of our knowledge, the coagulase activity has never been detected in extreme halophilic bacteria. Isolation and characterization of crude enzymes (especially coagulase) to investigate their properties and stability are in progress.The finding of novel enzymes with optimal activities at various ranges of salt concentrations is of great importance. Besides being intrinsically stable and active at high salt concentrations, halophilic and halotolerant enzymes offer great opportunities in biotechnological applications, such as environmental bioremediation (marine, oilfiel) and food processing. The bacterial isolates were also characterized for production of biosurfactants by oil-spread assay, measurement of surface tension and emulsification index (E24). There are few reports on biosurfactant producers in hypersaline environments and in recent years, there has been a greater increase in interest and importance in halophilic bacteria for biomolecules (Donio et al., 2013; Sarafin et al., 2014). Halophiles, which have a unique lipid composition, may have an important role to play as surface-active agents. The archae bacterial ether-linked phytanyl membrane lipid of the extremely halophilic bacteria has been shown to have surfactant properties (Post and Collins, 1982). Yakimov et al. (1995) reported the production of biosurfactant by a halotolerant Bacillus licheniformis strain BAS 50 which was able to produce a lipopeptide surfactant when cultured at salinities up to 13% NaCl. From solar salt, Halomonas sp. BS4 and Kocuria marina BS-15 were found to be able to produce biosurfactant when cultured at salinities of 8% and 10% NaCl respectively (Donio et al., 2013; Sarafin et al., 2014). In the present work, strains B4 and A4 produce biosurfactant in medium containing respectively 25% and 20% NaCl. To our knowledge, this is the first report on biosurfactant production by bacteria under such salt concentration. Biosurfactants have a wide variety of industrial and environmental applications (Akbari et al., 2018) but their applicability depends on their stability at different environmental conditions. The strain B4 which can produce biosurfactant at 25% NaCl showed good stability in alkaline pH and at a temperature range of 30°C-100°C. Due to the enormous utilization of biosurfactant in detergent manufacture the choice of alkaline biosurfactant is researched (Elazzazy et al., 2015). On the other hand, the interesting finding was the thermostability of the produced biosurfactant even after heat treatment (100°C for 30 min) which suggests the use of this biosurfactant in industries where heating is of a paramount importance (Khopade et al., 2012). To date, more attention has been focused on biosurfactant producing bacteria under extreme conditions for industrial and commercial usefulness. In fact, the biosurfactant produce by strain B4 have promising usefulness in pharmaceutical, cosmetics and food industries and for bioremediation in marine environment and Microbial enhanced oil recovery (MEOR) where the salinity, temperature and pH are high.CONCLUSIONThis is the first study on the culturable halophilic bacteria community inhabiting Chott Tinsilt in Eastern Algeria. Different genera of halotolerant bacteria with different phylogeneticaly characteristics have been isolated from this Chott. Culturing of bacteria and their molecular analysis provides an opportunity to have a wide range of cultured microorganisms from extreme habitats like hypersaline environments. Enzymes produced by halophilic bacteria show interesting properties like their ability to remain functional in extreme conditions, such as high temperatures, wide range of pH, and high salt concentrations. These enzymes have great economical potential in industrial, agricultural, chemical, pharmaceutical, and biotechnological applications. Thus, the halophiles isolated from Chott Tinsilt offer an important potential for application in microbial and enzyme biotechnology. In addition, these halo bacterial biosurfactants producers isolated from this Chott will help to develop more valuable eco-friendly products to the pharmacological and food industries and will be usefulness for bioremediation in marine environment and petroleum industry.ACKNOWLEDGMENTSOur thanks to Professor Abdelhamid Zoubir for proofreading the English composition of the present paper.CONFLICT OF INTERESTThe authors declare that they have no conflict of interest.Akbari, S., N. H. Abdurahman, R. M. Yunus, F. Fayaz and O. R. Alara, 2018. Biosurfactants—a new frontier for social and environmental safety: A mini review. Biotechnology research innovation, 2(1): 81-90.Association, A. P. H., A. W. W. Association, W. P. C. 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Globally, government is experiencing difficulties in generating adequate revenue to finance their activities. In Nigeria, studies have shown that the recent sharp reduction in the revenue was as a result of decline in crude oil prices which inversely affected the financial ability of government towards growth and development of the nation. To this end, this paper therefore investigated the effect of non-oil taxes on economic growth and development of Nigeria. The study employed ex-post facto research design. Macro data for the period 1994Q1-2017Q4 representing seventy six (76) observations were obtained from CBN statistical bulletin and National Bureau of Statistics. The documents were already exposed to the scrutiny of the appropriate regulatory agencies. The data were analyzed using descriptive and inferential statistics employing multiple regressions. The study discovered that non-oil taxes (custom and excise duties, capital gain tax, company income tax, tertiary education tax and value added tax) have significant effect on economic growth. (Adj. R2 = 0.75, F(5,71) = 213.43, p< .0.05). The individual effects are also positive and statistically significant: (VAT- β = 8.011, t(76)= 2.802, ρ<0.05, CIT- β = 2.560, t(76)= 2.383, ρ<0.05, CED - β = 1.767, t(76)=3.092, ρ<0.05, CGT- β = 4.162, t(76)= 3.509, ρ<0.05, and TET- β = 0.161, t(76)= 2.443, ρ<0.05). This study concluded that non-oil taxes significantly influenced both economic growth and economic development in Nigeria. The study recommended that government must strive to sustain the current unflinching commitment towards improving non-oil tax revenue, ensure Tertiary Education Tax collected translates into real development and also ensure efficient utilization of tax payers’ money to boost non-oil tax revenue collection which will then lead to economic growth and development.

Unconventional energy sources have become increasingly important to the global energy mix. These include coal seam gas, shale gas and shale oil. The unconventional gas industry was pioneered in the United States and embraced following the first oil shock in 1973 (Rogers). As has been the case with many global resources (Hiscock), many of the same companies that worked in the USA carried their experience in this industry to early Australian explorations. Recently the USA has secured significant energy security with the development of unconventional energy deposits such as the Marcellus shale gas and the Bakken shale oil (Dobb; McGraw). But this has not come without environmental impact, including contamination to underground water supply (Osborn, Vengosh, Warner, Jackson) and potential greenhouse gas contributions (Howarth, Santoro, Ingraffea; McKenna). The environmental impact of unconventional gas extraction has raised serious public concern about the introduction and growth of the industry in Australia. In coal rich Australia coal seam gas is currently the major source of unconventional gas. Large gas deposits have been found in prime agricultural land along eastern Australia, such as the Liverpool Plains in New South Wales and the Darling Downs in Queensland. Competing land-uses and a series of environmental incidents from the coal seam gas industry have warranted major protest from a coalition of environmentalists and farmers (Berry; McLeish). Conflict between energy companies wanting development and environmentalists warning precaution is an easy script to cast for frontline media coverage. But historical perspectives are often missing in these contemporary debates. While coal mining and natural gas have often received “boosting” historical coverage (Diamond; Wilkinson), and although historical themes of “development” and “rushes” remain predominant when observing the span of the industry (AGA; Blainey), the history of unconventional gas, particularly the history of its environmental impact, has been little studied. Few people are aware, for example, that the first shale gas exploratory well was completed in late 2010 in the Cooper Basin in Central Australia (Molan) and is considered as a “new” frontier in Australian unconventional gas. Moreover many people are unaware that the first coal seam gas wells were completed in 1976 in Queensland. The first four wells offer an important moment for reflection in light of the industry’s recent move into Central Australia. By locating and analysing the first four coal seam gas wells, this essay identifies the roots of the unconventional gas industry in Australia and explores the early environmental impact of these wells. By analysing exploration reports that have been placed online by the Queensland Department of Natural Resources and Mines through the lens of environmental history, the dominant developmental narrative of this industry can also be scrutinised. These narratives often place more significance on economic and national benefits while displacing the environmental and social impacts of the industry (Connor, Higginbotham, Freeman, Albrecht; Duus; McEachern; Trigger). This essay therefore seeks to bring an environmental insight into early unconventional gas mining in Australia. As the author, I am concerned that nearly four decades on and it seems that no one has heeded the warning gleaned from these early wells and early exploration reports, as gas exploration in Australia continues under little scrutiny. Arrival The first four unconventional gas wells in Australia appear at the beginning of the industry world-wide (Schraufnagel, McBane, and Kuuskraa; McClanahan). The wells were explored by Houston Oils and Minerals—a company that entered the Australian mining scene by sharing a mining prospect with International Australian Energy Company (Wiltshire). The International Australian Energy Company was owned by Black Giant Oil Company in the US, which in turn was owned by International Royalty and Oil Company also based in the US. The Texan oilman Robert Kanton held a sixteen percent share in the latter. Kanton had an idea that the Mimosa Syncline in the south-eastern Bowen Basin was a gas trap waiting to be exploited. To test the theory he needed capital. Kanton presented the idea to Houston Oil and Minerals which had the financial backing to take the risk. Shotover No. 1 was drilled by Houston Oil and Minerals thirty miles south-east of the coal mining town of Blackwater. By late August 1975 it was drilled to 2,717 metres, discovered to have little gas, spudded, and, after a spend of $610,000, abandoned. The data from the Shotover well showed that the porosity of the rocks in the area was not a trap, and the Mimosa Syncline was therefore downgraded as a possible hydrocarbon location. There was, however, a small amount of gas found in the coal seams (Benbow 16). The well had passed through the huge coal seams of both the Bowen and Surat basins—important basins for the future of both the coal and gas industries. Mining Concepts In 1975, while Houston Oil and Minerals was drilling the Shotover well, US Steel and the US Bureau of Mines used hydraulic fracture, a technique already used in the petroleum industry, to drill vertical surface wells to drain gas from a coal seam (Methane Drainage Taskforce 102). They were able to remove gas from the coal seam before it was mined and sold enough to make a profit. With the well data from the Shotover well in Australia compiled, Houston returned to the US to research the possibility of harvesting methane in Australia. As the company saw it, methane drainage was “a novel exploitation concept” and the methane in the Bowen Basin was an “enormous hydrocarbon resource” (Wiltshire 7). The Shotover well passed through a section of the German Creek Coal measures and this became their next target. In September 1976 the Shotover well was re-opened and plugged at 1499 meters to become Australia’s first exploratory unconventional gas well. By the end of the month the rig was released and gas production tested. At one point an employee on the drilling operation observed a gas flame “the size of a 44 gal drum” (HOMA, “Shotover # 1” 9). But apart from the brief show, no gas flowed. And yet, Houston Oil and Minerals was not deterred, as they had already taken out other leases for further prospecting (Wiltshire 4). Only a week after the Shotover well had failed, Houston moved the methane search south-east to an area five miles north of the Moura township. Houston Oil and Minerals had researched the coal exploration seismic surveys of the area that were conducted in 1969, 1972, and 1973 to choose the location. Over the next two months in late 1976, two new wells—Kinma No.1 and Carra No.1—were drilled within a mile from each other and completed as gas wells. Houston Oil and Minerals also purchased the old oil exploration well Moura No. 1 from the Queensland Government and completed it as a suspended gas well. The company must have mined the Department of Mines archive to find Moura No.1, as the previous exploration report from 1969 noted methane given off from the coal seams (Sell). By December 1976 Houston Oil and Minerals had three gas wells in the vicinity of each other and by early 1977 testing had occurred. The results were disappointing with minimal gas flow at Kinma and Carra, but Moura showed a little more promise. Here, the drillers were able to convert their Fairbanks-Morse engine driving the pump from an engine run on LPG to one run on methane produced from the well (Porter, “Moura # 1”). Drink This? Although there was not much gas to find in the test production phase, there was a lot of water. The exploration reports produced by the company are incomplete (indeed no report was available for the Shotover well), but the information available shows that a large amount of water was extracted before gas started to flow (Porter, “Carra # 1”; Porter, “Moura # 1”; Porter, “Kinma # 1”). As Porter’s reports outline, prior to gas flowing, the water produced at Carra, Kinma and Moura totalled 37,600 litres, 11,900 and 2,900 respectively. It should be noted that the method used to test the amount of water was not continuous and these amounts were not the full amount of water produced; also, upon gas coming to the surface some of the wells continued to produce water. In short, before any gas flowed at the first unconventional gas wells in Australia at least 50,000 litres of water were taken from underground. Results show that the water was not ready to drink (Mathers, “Moura # 1”; Mathers, “Appendix 1”; HOMA, “Miscellaneous Pages” 21-24). The water had total dissolved solids (minerals) well over the average set by the authorities (WHO; Apps Laboratories; NHMRC; QDAFF). The well at Kinma recorded the highest levels, almost two and a half times the unacceptable standard. On average the water from the Moura well was of reasonable standard, possibly because some water was extracted from the well when it was originally sunk in 1969; but the water from Kinma and Carra was very poor quality, not good enough for crops, stock or to be let run into creeks. The biggest issue was the sodium concentration; all wells had very high salt levels. Kinma and Carra were four and two times the maximum standard respectively. In short, there was a substantial amount of poor quality water produced from drilling and testing the three wells. Fracking Australia Hydraulic fracturing is an artificial process that can encourage more gas to flow to the surface (McGraw; Fischetti; Senate). Prior to the testing phase at the Moura field, well data was sent to the Chemical Research and Development Department at Halliburton in Oklahoma, to examine the ability to fracture the coal and shale in the Australian wells. Halliburton was the founding father of hydraulic fracture. In Oklahoma on 17 March 1949, operating under an exclusive license from Standard Oil, this company conducted the first ever hydraulic fracture of an oil well (Montgomery and Smith). To come up with a program of hydraulic fracturing for the Australian field, Halliburton went back to the laboratory. They bonded together small slabs of coal and shale similar to Australian samples, drilled one-inch holes into the sample, then pressurised the holes and completed a “hydro-frac” in miniature. “These samples were difficult to prepare,” they wrote in their report to Houston Oil and Minerals (HOMA, “Miscellaneous Pages” 10). Their program for fracturing was informed by a field of science that had been evolving since the first hydraulic fracture but had rapidly progressed since the first oil shock. Halliburton’s laboratory test had confirmed that the model of Perkins and Kern developed for widths of hydraulic fracture—in an article that defined the field—should also apply to Australian coals (Perkins and Kern). By late January 1977 Halliburton had issued Houston Oil and Minerals with a program of hydraulic fracture to use on the central Queensland wells. On the final page of their report they warned: “There are many unknowns in a vertical fracture design procedure” (HOMA, “Miscellaneous Pages” 17). In July 1977, Moura No. 1 became the first coal seam gas well hydraulically fractured in Australia. The exploration report states: “During July 1977 the well was killed with 1% KCL solution and the tubing and packer were pulled from the well … and pumping commenced” (Porter 2-3). The use of the word “kill” is interesting—potassium chloride (KCl) is the third and final drug administered in the lethal injection of humans on death row in the USA. Potassium chloride was used to minimise the effect on parts of the coal seam that were water-sensitive and was the recommended solution prior to adding other chemicals (Montgomery and Smith 28); but a word such as “kill” also implies that the well and the larger environment were alive before fracking commenced (Giblett; Trigger). Pumping recommenced after the fracturing fluid was unloaded. Initially gas supply was very good. It increased from an average estimate of 7,000 cubic feet per day to 30,000, but this only lasted two days before coal and sand started flowing back up to the surface. In effect, the cleats were propped open but the coal did not close and hold onto them which meant coal particles and sand flowed back up the pipe with diminishing amounts of gas (Walters 12). Although there were some interesting results, the program was considered a failure. In April 1978, Houston Oil and Minerals finally abandoned the methane concept. Following the failure, they reflected on the possibilities for a coal seam gas industry given the gas prices in Queensland: “Methane drainage wells appear to offer no economic potential” (Wooldridge 2). At the wells they let the tubing drop into the hole, put a fifteen foot cement plug at the top of the hole, covered it with a steel plate and by their own description restored the area to its “original state” (Wiltshire 8). Houston Oil and Minerals now turned to “conventional targets” which included coal exploration (Wiltshire 7). A Thousand Memories The first four wells show some of the critical environmental issues that were present from the outset of the industry in Australia. The process of hydraulic fracture was not just a failure, but conducted on a science that had never been tested in Australia, was ponderous at best, and by Halliburton’s own admission had “many unknowns”. There was also the role of large multinationals providing “experience” (Briody; Hiscock) and conducting these tests while having limited knowledge of the Australian landscape. Before any gas came to the surface, a large amount of water was produced that was loaded with a mixture of salt and other heavy minerals. The source of water for both the mud drilling of Carra and Kinma, as well as the hydraulic fracture job on Moura, was extracted from Kianga Creek three miles from the site (HOMA, “Carra # 1” 5; HOMA, “Kinma # 1” 5; Porter, “Moura # 1”). No location was listed for the disposal of the water from the wells, including the hydraulic fracture liquid. Considering the poor quality of water, if the water was disposed on site or let drain into a creek, this would have had significant environmental impact. Nobody has yet answered the question of where all this water went. The environmental issues of water extraction, saline water and hydraulic fracture were present at the first four wells. At the first four wells environmental concern was not a priority. The complexity of inter-company relations, as witnessed at the Shotover well, shows there was little time. The re-use of old wells, such as the Moura well, also shows that economic priorities were more important. Even if environmental information was considered important at the time, no one would have had access to it because, as handwritten notes on some of the reports show, many of the reports were “confidential” (Sell). Even though coal mines commenced filing Environmental Impact Statements in the early 1970s, there is no such documentation for gas exploration conducted by Houston Oil and Minerals. A lack of broader awareness for the surrounding environment, from floral and faunal health to the impact on habitat quality, can be gleaned when reading across all the exploration reports. Nearly four decades on and we now have thousands of wells throughout the world. Yet, the challenges of unconventional gas still persist. The implications of the environmental history of the first four wells in Australia for contemporary unconventional gas exploration and development in this country and beyond are significant. Many environmental issues were present from the beginning of the coal seam gas industry in Australia. Owning up to this history would place policy makers and regulators in a position to strengthen current regulation. The industry continues to face the same challenges today as it did at the start of development—including water extraction, hydraulic fracturing and problems associated with drilling through underground aquifers. Looking more broadly at the unconventional gas industry, shale gas has appeared as the next target for energy resources in Australia. Reflecting on the first exploratory shale gas wells drilled in Central Australia, the chief executive of the company responsible for the shale gas wells noted their deliberate decision to locate their activities in semi-desert country away from “an area of prime agricultural land” and conflict with environmentalists (quoted in Molan). Moreover, the journalist Paul Cleary recently complained about the coal seam gas industry polluting Australia’s food-bowl but concluded that the “next frontier” should be in “remote” Central Australia with shale gas (Cleary 195). It appears that preference is to move the industry to the arid centre of Australia, to the ecologically and culturally unique Lake Eyre Basin region (Robin and Smith). 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NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Dam, G., Nøhr-Hansen, H., Christiansen, F. G., Bojesen-Koefoed, J. A., & Laier, T. (1998). The oldest marine Cretaceous sediments in West Greenland (Umiivik-1 borehole) – record of the Cenomanian–Turonian Anoxic Event?. Geology of Greenland Survey Bulletin, 180, 128-137. https://doi.org/10.34194/ggub.v180.5096 _______________ The stratigraphic borehole Umiivik-1 on Svartenhuk Halvø was drilled in August–September 1995 as part of a joint programme between the Government of Greenland, Minerals Office (now Bureau of Minerals and Petroleum) and the Danish State (Mineral Resources Administration for Greenland). The joint programme was based on a political decision from November 1994 made in order to attract the oil and mineral industry to Greenland. The drilling of Umiivik-1 is one of several petroleum geological projects in West Greenland that were initiated early in 1995. Analyses on the core include detailed sedimentological, palynological and organic geochemical studies. The other petroleum geological projects comprise: description and interpretation of the three exploration boreholes on Nuussuaq, GANT#1, GANE#1 and GANK#1 that the Canadian oil company grønArctic Energy Inc. drilled in the summer of 1995 (e.g. Christiansen et al. 1996a, c; Dam 1996a–c; NøhrHansen 1997a); seismic surveys in the fjords around Disko, Nuussuaq and Svartenhuk Halvø (FjordSeis 95); seismic surveys in the offshore area between 68° and 71°N (DiskoSeis 95); and seismic surveys in the offshore area south of 68°N (IkerSeis 95, KangaSeis 95 and ExtraSeis 95; Chalmers et al. 1998, this volume; Skaarup & Chalmers 1998, this volume). The prime objective of Umiivik-1 was to document oil-prone source rocks in mid-Cretaceous strata. Although several types of crude oil have been found in seeps and slim-hole cores in West Greenland since 1992, there was only limited knowledge on actual source rocks when the project was initiated. Detailed organic geochemistry, especially the distribution of biomarkers in seeping oils, provides important information on the type of organic material, the depositional environment and the thermal history of the source rocks that generated these oils (Christiansen et al. 1996b, 1997b; Bojesen-Koefoed et al. in press). However, there are only limited data on thickness, areal distribution, generative potential, and stratigraphic age of the actual source rocks. Considering the exploration possibilities in West Greenland, the presence of source rocks seems to be one of the main risk elements, if not the most critical factor. It was therefore generally accepted in 1994 that the level of exploration interest in West Greenland would strongly benefit from the actual demonstration of the existence, age and depositional environment of oil-prone source rocks and by quantifying their generation potential. The most likely candidate in this context was a possible mid-Cretaceous marine source rock (Cenomanian–Turonian) that was first suggested in West Greenland by Chalmers et al. (1993) on the basis of world-wide analogies, but later supported by direct data from Ellesmere Island in Arctic Canada (Núñez-Betelu 1994). The Svartenhuk Halvø area is one of the few areas where Upper Cretaceous and Lower Tertiary marine sediments are exposed onshore West Greenland (Fig. 1), and the mudstones outcropping on Svartenhuk Halvø are the oldest known, fully marine deposits from West Greenland (Birkelund 1965; Nøhr-Hansen 1996). These mudstones have recently been studied during field work by the Geological Survey of Greenland in 1991 and 1992, a programme which also included five shallow boreholes between 66 and 86 m deep (Fig. 1; Christiansen 1993; Christiansen et al. 1994). Based on analytical work from these cores and samples from nearby outcrops, thermally immature mudstones of Coniacian to Early Santonian age have been documented (Nøhr-Hansen 1996), thereby giving hope that immature or early mature sediments of Cenomanian– Turonian age could be reached by drilling to relatively shallow depths along the southern shoreline of Umiiviup Kangerlua (Fig. 1).