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Journal articles on the topic 'Mesophiles'

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Published: 4 June 2021
Last updated: 1 February 2022

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1

Pollo, Stephen M. J., Olga Zhaxybayeva, and Camilla L. Nesbø. "Insights into thermoadaptation and the evolution of mesophily from the bacterial phylum Thermotogae." Canadian Journal of Microbiology 61, no. 9 (September 2015): 655–70. http://dx.doi.org/10.1139/cjm-2015-0073.

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Thermophiles are extremophiles that grow optimally at temperatures >45 °C. To survive and maintain function of their biological molecules, they have a suite of characteristics not found in organisms that grow at moderate temperature (mesophiles). At the cellular level, thermophiles have mechanisms for maintaining their membranes, nucleic acids, and other cellular structures. At the protein level, each of their proteins remains stable and retains activity at temperatures that would denature their mesophilic homologs. Conversely, cellular structures and proteins from thermophiles may not function optimally at moderate temperatures. These differences between thermophiles and mesophiles presumably present a barrier for evolutionary transitioning between the 2 lifestyles. Therefore, studying closely related thermophiles and mesophiles can help us determine how such lifestyle transitions may happen. The bacterial phylum Thermotogae contains hyperthermophiles, thermophiles, mesophiles, and organisms with temperature ranges wide enough to span both thermophilic and mesophilic temperatures. Genomic, proteomic, and physiological differences noted between other bacterial thermophiles and mesophiles are evident within the Thermotogae. We argue that the Thermotogae is an ideal group of organisms for understanding of the response to fluctuating temperature and of long-term evolutionary adaptation to a different growth temperature range.
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2

Korehi, Hananeh, and Axel Schippers. "Bioleaching of a Marine Hydrothermal Sulfide Ore with Mesophiles, Moderate Thermophiles and Thermophiles." Advanced Materials Research 825 (October 2013): 229–32. http://dx.doi.org/10.4028/www.scientific.net/amr.825.229.

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Marine hydrothermal polymetallic sulfide ores contain high amounts of valuable metals such as Cu, Pb, Zn, Au, Ag, as well as In, Ge, Bi, and Se. Samples from a site in the Indian Ocean were taken during a BGR ship cruise, crushed and sieved for bioleaching experiments to reveal the extraction of the various metals. Chalcopyrite was the main mineral, the total copper content was 38.5 %wt. Comparative bioleaching with mesophilic, moderate thermophilic and thermophilic acidophilic iron- and sulfur-oxidizing bacteria and archaea was investigated. Batch culture experiments were conducted at 2% (w/v) pulp density in shake flasks in the presence of Acidithiobacillus ferrooxidans, Acidiphilium sp. and Acidithiobacillus thiooxidans as mesophiles (30°C), a mixed culture of moderate thermopilic iron- and sulfur oxidizing bacteria (50°C) and the thermophile Acidianus brierleyi (70°C). The results after four weeks showed most effective dissolution of copper in the presence of A. brierleyi (up to 4.3 g/l), compared with moderate thermophiles and mesophiles (3.3 g/l and 2.5 g/l, respectively). Furthermore, the bioleaching performance was approved with dissolved iron concentrations. Conclusively, an increase in temperature from 30 °C to 70 °C had a major impact on bioleaching efficiency. Copper and iron extraction efficiency occurred in the order thermophiles, moderate thermophiles, mesophiles.
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3

Ramos, Cleusa Fernandes, Andreia Assuncao Soares, Isabela Carvalho dos Santos, Felipe Andre Pereira Ramos, Odair Alberton, Luciana Kazue Otutumi, Lidiane Nunes Barbosa, Ricardo de Melo Germano, Daniela Dib Goncalves, and Luiz Sergio Merlini. "Heat Treatment Reduces Bacterial Contamination of Medicinal Plants Grown in A Community Garden." Journal of Pure and Applied Microbiology 14, no. 3 (September 16, 2020): 1817–23. http://dx.doi.org/10.22207/jpam.14.3.20.

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The verification of microorganisms that indicate contamination of medicinal plants cultivated in vegetable gardens is fundamental to contribute and improve the conditions and management of the garden, providing safer and healthier food for the consumer population. The study aims to evaluate the bacteriological quality of Cymbopogon citratus, Aloysia citriodora, Plectranthus barbalus, Aloe vera (L.) Burm. F., Sedum dendroideum, and Peumus boldus cultivated in community gardens. Six samples were randomly collected from each plant and sent to the Laboratory of Veterinary Preventive Medicine and Public Health at Universidade Paranaense-UNIPAR, for bacteriological analysis (aerobic mesophilic microorganisms, total coliforms and coliforms at 45ºC. The cold extract (room temperature) of the medicinal plants evaluated, the Plectranthus barbalus had the highest mean for aerobic mesophiles (1.26 CFU/g x 106) and the Cymbopogon citratus second highest mean for aerobic mesophiles (9.80 CFU/g x 105). In the coliform count at 45°C, the highest mean was found in the Aloysia citriodora (2.90 CFU/g x 103) and it presented the second lowest mean for coliforms at 45°C (0.63 CFU/g x 103) and was zero for total coliforms. Regarding the hot extract (95°C-100°C) of the medicinal plants evaluated, a significantly higher aerobic mesophiles count was found for Aloysia citriodora when compared with Aloe vera (L.) Burm. F., Sedum dendroideum and Peumus boldus, not differing statistically from Cymbopogon citratus and Plectranthus barbalus. It was found that medicinal plants are contaminated but, since they are indicated as teas (infusion), they are safe for their consumers because the risk of bacteriological contamination can be considerably eliminated or reduced due to the boiling process.
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4

FUJIKAWA, HIROSHI, and TAKESHI ITOH. "Thermal Inactivation Analysis of Mesophiles Using the Arrhenius and z-Value Models." Journal of Food Protection 61, no. 7 (July 1, 1998): 910–12. http://dx.doi.org/10.4315/0362-028x-61.7.910.

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The Arrhenius and z-value models were compared for thermal inactivation analysis of a mesophilic bacterium. The models produced a linear curve for the thermal inactivation data. Concerning the rate constant of inactivation, the D and k values predicted by the models at a constant temperature were similar. For extrapolated temperatures the z-value model predicted an insignificant decrease in the survival ratio compared to the Arrhenius model. The dynamic temperature survival curves predicted by the models were similar, and the models characterized the results. These results demonstrated that the models can be used for thermal inactivation analysis of mesophiles at various temperatures.
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5

Seel, Waldemar, Julia Derichs, and André Lipski. "Increased Biomass Production by Mesophilic Food-Associated Bacteria through Lowering the Growth Temperature from 30°C to 10°C." Applied and Environmental Microbiology 82, no. 13 (April 15, 2016): 3754–64. http://dx.doi.org/10.1128/aem.00211-16.

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ABSTRACTFive isolates from chilled food and refrigerator inner surfaces and closely related reference strains of the speciesEscherichia coli,Listeria monocytogenes,Staphylococcus xylosus,Bacillus cereus,Pedobacter nutrimenti, andPedobacter panaciterraewere tested for the effect of growth temperature (30°C and 10°C) on biomass formation. Growth was monitored via optical density, and biomass formation was measured at the early stationary phase based on the following parameters in complex and defined media: viable cell count, total cell count, cell dry weight, whole-cell protein content, and cell morphology. According to the lack of growth at 1°C, all strains were assigned to the thermal class of mesophiles. Glucose and ammonium consumption related to cell yield were analyzed in defined media. Except for the protein content, temperature had a significant (ttest,P< 0.05) effect on all biomass formation parameters for each strain. The results show a significant difference between the isolates and the related reference strains. Isolates achieved an increase in biomass production between 20% and 110% at the 10°C temperature, which is 15 to 25°C lower than their maximum growth rate temperatures. In contrast, reference strains showed a maximum increase of only about 25%, and some reference strains showed no increase or a decrease of approximately 25%. As expected, growth rates for all strains were higher at 30°C than at 10°C, while biomass production for isolates was higher at 10°C than at 30°C. In contrast, the reference strains showed similar growth yields at the two temperatures. This also demonstrates for mesophilic bacterial strains more efficient nutrient assimilation during growth at low temperatures. Until now, this characteristic was attributed only to psychrophilic microorganisms.IMPORTANCEFor several psychrophilic species, increased biomass formation was described at temperatures lower than optimum growth temperatures, which are defined by the highest growth rate. This work shows increased biomass formation at low growth temperatures for mesophilic isolates. A comparison with closely related reference strains from culture collections showed a significantly smaller increase or no increase in biomass formation. This indicates a loss of specific adaptive mechanisms (e.g., cold adaptation) for mesophiles during long-term cultivation. The increased biomass production for mesophiles under low-temperature conditions opens new avenues for a more efficient biotechnological transformation of nutrients to microbial biomass. These findings may also be important for risk assessment of cooled foods since risk potential is often correlated with the cell numbers present in food samples.
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6

Herrera-Mejía, María Juliana, Alfonso Tullio Sarmiento, and Luz Indira Sotelo-Díaz. "Predictive model of microorganism mesophiles in processed meat products during storage under fluctuating temperatures1." DYNA 86, no. 208 (January 1, 2019): 46–52. http://dx.doi.org/10.15446/dyna.v86n208.66777.

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The aim of this investigation was to develop a predictive model of microorganism mesophiles in processed meat products during storage under fluctuating temperatures between 1°C to 7°C to establish the shelf removal date of the products based on mesophile limits established by Colombian Technical Standard NTC 1325 of 2008 for non-canned processed meat products. The variables used in the model were as follows: temperature, storage time and population of microorganisms at the beginning of storage. The S curve of the growth of the microorganisms was approximated by sections using a multivariate quadratic regression equation. The model achieved 91% accuracy for the prediction of the shelf removal date. In terms of practicality, the model offers a simpler alternative to traditional models for the prediction of microorganisms that require a greater amount of parameters and data.
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7

Vilcáez, Javier, Koichi Suto, and Chihiro Inoue. "Modeling the Auto-Thermal Performance of a Thermophilic Chalcopyrite Bioleaching Heap Employing Mesophilic and Thermophilic Microbes." Advanced Materials Research 20-21 (July 2007): 70–74. http://dx.doi.org/10.4028/www.scientific.net/amr.20-21.70.

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A model was prepared to study the performance of a thermophilic bioleaching heap that employs mixed mesophilic and thermophilic microbes for copper extraction from CuFeS2. Mesophiles’ preference for and ease of dissolving additional FeS2 provided to the heap enables the transition from a mesophilic to a thermophilic bioleaching state without the necessity of additional energy supply. In this sense, the mathematical description of the bioleaching process is done taking into consideration the dependency of both microbes’ biological states on physicochemical factors such as the temperature and O2 availability. With regard to the flow rates of the liquid and air phases, simulation results have shown that these flow rates govern not just the heat transfer and variation of cell distribution, but also the leaching rate regardless of the fraction of CuFeS2 per FeS2 leached (FCP) which is the other variable influencing to the heat accumulation in the heap.
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8

PRIETO, MIGUEL, MARÍA L. GARCÍA, MARÍA R. GARCÍA, ANDRÉS OTERO, and BENITO MORENO. "Distribution and Evolution of Bacteria on Lamb Carcasses During Aerobic Storage." Journal of Food Protection 54, no. 12 (December 1, 1991): 945–49. http://dx.doi.org/10.4315/0362-028x-54.12.945.

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The change of bacterial counts during storage life of chilled (3±1°C) lamb carcasses was determined by sampling at 0, 5, 10, and 15 d postslaughter and at the spoilage time. Three sites (neck, brisket, and leg) of each carcass were sampled using three sampling methods (swabbing, scraping, and excision of the swabbed and scraped areas). After slaughter, mean count of mesophiles (30°C) was 4.96 log10 CFU/cm2. The initial mean count of psychrotrophs (7°C) expressed as a percentage of the mean count of mesophiles was 33.4%. The mean values of mesophiles and psychrotrophs associated with spoilage were 7.4 log10/cm2 and 7.95 log10/cm2, respectively. Carcasses always had pH values above 5.8 and kept unspoiled 23–29 d. Brisket and leg were the most contaminated areas. Percentages of bacteria recovered by scraping were higher than those obtained by swabbing (ca. 20%). Bacterial counts were significantly affected by day of storage (p&lt;0.001), sampling point (p&lt;0.001), and temperature of incubation (p&lt;0.05). Interaction between sampling day and sampling site was also observed.
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9

THOMAS, M. Theresa, and K. Robert SCOPES. "The effects of temperature on the kinetics and stability of mesophilic and thermophilic 3-phosphoglycerate kinases." Biochemical Journal 330, no. 3 (March 15, 1998): 1087–95. http://dx.doi.org/10.1042/bj3301087.

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The effects of temperature on the kinetic parameters kcat and Km, for three isolates of the highly conserved monomeric enzyme 3-phosphoglycerate kinase (PGK), were investigated in detail using a rapid automated kinetics apparatus. PGK was purified from the thermophilic bacterium Thermoanaerobacter sp. Rt8.G4 (optimum growth temperature 68 °C), the mesophile Zymomonas mobilis (optimum growth temperature 32 °C) and a second, unidentified, soil mesophile designated unid A (optimum growth temperature 27 °C). The kinetic behaviour with temperature of each PGK preparation was distinct, despite the conserved nature of the enzyme. The kcat values increased with temperature, but not as rapidly exponentially, as might be expected from the Arrhenius equation. Maximum kcat values were at much higher temperatures than the optimum growth temperatures for the mesophiles, but for the thermophile the temperature of maximum kcat was close to its optimum growth temperature. Km values were in general nearly constant through the lower temperature ranges, but increased substantially as the optimum temperature (highest kcat) was passed. Thermal irreversible denaturation of the PGK proteins was also investigated by measuring loss of activity over time. In a dilute buffer, Arrhenius plots for denaturation were linear, and the calculated apparent energy of activation (Eact) for denaturation for the thermophilic PGK was 600 kJ·mol-1, whereas for the mesophilic enzymes the values were 200-250 kJ·mol-1. In the presence of substrates, a considerable stabilization occurred, and in the case of the Z. mobilis enzyme, the apparent Eact was increased to 480 kJ·mol-1. A theoretical explanation for these observations is presented. Comparing the kinetics data with irreversible denaturation rates determined at relevant temperatures, it was clear that kcat values reached a maximum, and then decreased with higher temperature before irreversible denaturation had any significant influence.
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10

Jaafar, Nardiah Rizwana, Dene Littler, Travis Beddoe, Jamie Rossjohn, Rosli Md Illias, Nor Muhammad Mahadi, Mukram Mohamed Mackeen, Abdul Munir Abdul Murad, and Farah Diba Abu Bakar. "Crystal structure of fuculose aldolase from the Antarctic psychrophilic yeastGlaciozyma antarcticaPI12." Acta Crystallographica Section F Structural Biology Communications 72, no. 11 (October 27, 2016): 831–39. http://dx.doi.org/10.1107/s2053230x16015612.

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Fuculose-1-phosphate aldolase (FucA) catalyses the reversible cleavage of L-fuculose 1-phosphate to dihydroxyacetone phosphate (DHAP) and L-lactaldehyde. This enzyme from mesophiles and thermophiles has been extensively studied; however, there is no report on this enzyme from a psychrophile. In this study, the gene encoding FucA fromGlaciozyma antarcticaPI12 (GaFucA) was cloned and the enzyme was overexpressed inEscherichia coli, purified and crystallized. The tetrameric structure of GaFucA was determined to 1.34 Å resolution. The overall architecture of GaFucA and its catalytically essential histidine triad are highly conserved among other fuculose aldolases. Comparisons of structural features between GaFucA and its mesophilic and thermophilic homologues revealed that the enzyme has typical psychrophilic attributes, indicated by the presence of a high number of nonpolar residues at the surface and a lower number of arginine residues.
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11

ALONSO-CALLEJA, CARLOS, JAVIER CARBALLO, ROSA CAPITA, ANA BERNARDO, and MARÍA LUISA GARCÍA-LÓPEZ. "Evaluation of the Spiral Plating Method for the Enumeration of Microorganisms throughout the Manufacturing and Ripening of a Raw Goat's Milk Cheese." Journal of Food Protection 65, no. 2 (February 1, 2002): 339–44. http://dx.doi.org/10.4315/0362-028x-65.2.339.

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A statistical comparison of the spiral plate count (SPLPC) and the standard plate count (SPC) methods for enumeration of microorganisms in raw goat's milk cheese throughout its manufacturing and ripening was carried out. Enumeration of mesophiles, lactic acid bacteria (presumptive lactococci, presumptive leuconostocs, and presumptive lactobacilli), Micrococcaceae, Enterobacteriaceae, and molds and yeasts was carried out for milk, curd, and 2-, 5-, 10-, 17-, and 27-day-old cheeses. Average counts for the SPLPC and SPC methods differed by less than half of a log cycle for all microbial groups studied (range of difference, −0.1386 [mesophiles] to +0.4397 [presumptive lactobacilli]). The results of the SPLPC method compared favorably with the results of the SPC procedure for mesophiles, presumptive lactococci, presumptive leuconostocs, Enterobacteriaceae, and molds and yeasts (the variance between replicate platings was close to 0.005, and correlation coefficients were &gt;0.9). Correlation coefficients were lower for Micrococcaceae (r = 0.824) and presumptive lactobacilli (r = 0.670). Analysis of variance showed that the plating method was a significant factor (P &lt; 0.05) for presumptive lactobacilli counts. In general, results from the SPLPC method compared favorably with results from SPC procedure in the enumeration of microorganisms in goat cheese throughout its manufacturing and ripening processes. However, the suitability of the SPLPC method depends mainly on the microbial group studied.
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12

JAY, JAMES M., and MAY E. BUE. "Ineffectiveness of Crystal Violet Tetrazolium Agar for Determining Psychrotrophic Gram-Negative Bacteria." Journal of Food Protection 50, no. 2 (February 1, 1987): 147–49. http://dx.doi.org/10.4315/0362-028x-50.2.147.

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Gram-negative psychrotrophic and nonpsychrotrophic mesophiles grew equally well on crystal violet tetrazolium (CVT) agar at 30°C in 48 h, hence this medium is not suitable for enumerating or recognizing psychrotrophic bacteria.
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13

KOSEKI, SHIGENOBU, KYOICHIRO YOSHIDA, SEIICHIRO ISOBE, and KAZUHIKO ITOH. "Efficacy of Acidic Electrolyzed Water for Microbial Decontamination of Cucumbers and Strawberries." Journal of Food Protection 67, no. 6 (June 1, 2004): 1247–51. http://dx.doi.org/10.4315/0362-028x-67.6.1247.

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An examination was made of the efficacy of acidic electrolyzed water (AcEW, 30 ppm free available chlorine), ozonated water (5 ppm ozone), and a sodium hypochlorite solution (NaOCl, 150 ppm free available chlorine) for use as potential sanitizers of cucumbers and strawberries. AcEW and NaOCl reduced the aerobic mesophiles naturally present on cucumbers within 10 min by 1.4 and 1.2 log CFU per cucumber, respectively. The reduction by ozonated water (0.7 log CFU per cucumber) was significantly less than that of AcEW or NaOCl (P ≤ 0.05). Cucumbers washed in alkaline electrolyzed water for 5 min and then treated with AcEW for 5 min showed a reduction in aerobic mesophiles that was at least 2 log CFU per cucumber greater than that of other treatments (P ≤ 0.05). This treatment was also effective in reducing levels of coliform bacteria and fungi associated with cucumbers. All treatments offered greater microbial reduction on the cucumber surface than in the cucumber homogenate. Aerobic mesophiles associated with strawberries were reduced by less than 1 log CFU per strawberry after each treatment. Coliform bacteria and fungi associated with strawberries were reduced by 1.0 to 1.5 log CFU per strawberry after each treatment. Microbial reduction was approximately 0.5 log CFU per strawberry greater on the strawberry surface than in the strawberry homogenate. However, neither treatment was able to completely inactivate or remove the microorganisms from the surface of the cucumber or strawberry.
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14

ROBLES-GANCEDO, S., T. M. LÓPEZ-DÍAZ, and A. OTERO. "Microbiological Counts during Beet Sugar Extraction." Journal of Food Protection 72, no. 6 (June 1, 2009): 1332–37. http://dx.doi.org/10.4315/0362-028x-72.6.1332.

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In order to discover the main microbial populations present throughout the process of beet sugar extraction and to identify the steps where possible control measures could be implemented, four Spanish beet sugar extraction factories were investigated. Eighteen stages were sampled at each factory and analyzed for several microbial groups and physicochemical parameters. Beets, cossettes, and diffusion juices were the most contaminated samples during beet sugar extraction, and mesophiles, thermophiles, and yeasts were the most numerous microbiota. Differences in contamination among factories and among stages of the sugar extraction process were statistically significant (P &lt; 0.01). Beets and cossettes showed high numbers of mesophiles and lactic acid bacteria, with gum-forming bacteria and yeasts being at levels of &gt;6 log CFU/g. Diffusion juices were highly contaminated with aerobic mesophiles, lactic acid bacteria, and thermophiles. Beet-washing water, equipment, and air were also important sources of contamination; in contrast, diffusion water showed moderate levels of microorganisms due to the acid treatment performed. Gum-forming bacteria, which are present at high levels from the first step of the extraction, survive the diffusion process and remain in the diffusion juice, where they may produce “gums” responsible for obstruction of filters. Thermophiles were present, although at levels lower than expected in most samples. Other microbial groups, particularly yeasts, may also contribute to the destruction of sugar. No biocides were used during the beet sugar extraction in the factories investigated.
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15

Delazeri, Dailis, Heloísa Bertagnon, Melina A. Bonato, and Liliana L. Borges. "59 Autolized yeast reduces microbiological contamination of the carcass in steers finished in a feedlot." Journal of Animal Science 98, Supplement_4 (November 3, 2020): 35. http://dx.doi.org/10.1093/jas/skaa278.063.

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Abstract The use of feed additives based on yeast cell wall has already been studied to favor the growth of beneficial intestinal bacteria to the detriment of pathogenic bacteria in ruminants. This fact reduces diarrhea, increases animal performance, and could promote lesser contamination of the bovine carcass at the time of slaughter, during the evisceration. The present study aims to verify if the yeast cell wall of Saccharomyces cerevisiae autolyzed yeast (AY) reduces total coliforms and Escherichia coli in feces and bovine carcass. Therefore, 36 steers, ½ Angus blood, finished in a feedlot, were submitted to three daily treatments for 105 days: control (diet without yeast), AY 4g (4g/animal/day, 2 x 1010cel/g of a commercial product based on Saccharomyces cerevisiae RumenYeast®), AY 7g (7g/animal/day, RumenYeast®). On days 29 and 90, after beginning in the feedlot, samples of feces were collected for E. coli and total coliforms identifications and counting. On the day of slaughter, 4 points of the carcasses were collected to identify and quantify E. coli, total fecal coliforms, and mesophiles by a petrifilm methodology. There was a reduction in E. coli and total coliforms for the AY 7g in the fecal samples comparing to the other groups (P = 0.0008 and 0.008, respectively), and a trend to reduce E. coli, total coliforms and mesophilic aerobes in the bovine carcass in AY 4g and AY 7g, comparing to the control group (P = 0.06; 0.10, and 0.05, respectively). It was concluded that supplementation with autolyzed yeast, especially when utilized in higher doses (7g), reduced fecal excretion and, consequently, reduce the carcass contamination by E. coli, mesophiles, and, total coliforms in animals during the feedlot period.
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Annweiler, E., H. H. Richnow, G. Antranikian, S. Hebenbrock, C. Garms, S. Franke, W. Francke, and W. Michaelis. "Naphthalene Degradation and Incorporation of Naphthalene-Derived Carbon into Biomass by the ThermophileBacillus thermoleovorans." Applied and Environmental Microbiology 66, no. 2 (February 1, 2000): 518–23. http://dx.doi.org/10.1128/aem.66.2.518-523.2000.

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ABSTRACT The thermophilic aerobic bacterium Bacillus thermoleovorans Hamburg 2 grows at 60°C on naphthalene as the sole source of carbon and energy. In batch cultures, an effective substrate degradation was observed. The carbon balance, including naphthalene, metabolites, biomass, and CO2, was determined by the application of [1-13C]naphthalene. The incorporation of naphthalene-derived carbon into the bulk biomass as well as into specified biomass fractions such as fatty acids and amino acids was confirmed by coupled gas chromatography-mass spectrometry (GC-MS) and isotope analyses. Metabolites were characterized by GC-MS; the established structures allow tracing the degradation pathway under thermophilic conditions. Apart from typical metabolites of naphthalene degradation known from mesophiles, intermediates such as 2,3-dihydroxynaphthalene, 2-carboxycinnamic acid, and phthalic and benzoic acid were identified for the pathway of this bacterium. These compounds indicate that naphthalene degradation by the thermophilicB. thermoleovorans differs from the known pathways found for mesophilic bacteria.
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A. Abd, Abdul-Hadi, Nadia I. AbdulA?Al, and Aysar S. Abood. "Prevalence of Thermophiles and Mesophiles in Raw and UHT Milk." International Journal of Animal and Veterinary Advances 6, no. 1 (February 20, 2014): 23–27. http://dx.doi.org/10.19026/ijava.6.5612.

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18

Rousseau, Benjamin J. G., Shoresh Shafei, Agostino Migliore, Robert J. Stanley, and David N. Beratan. "Determinants of Photolyase’s DNA Repair Mechanism in Mesophiles and Extremophiles." Journal of the American Chemical Society 140, no. 8 (February 13, 2018): 2853–61. http://dx.doi.org/10.1021/jacs.7b11926.

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19

Matsuo, Yoshihide, Atsuko Katsuta, Satoru Matsuda, Yoshikazu Shizuri, Akira Yokota, and Hiroaki Kasai. "Mechercharimyces mesophilus gen. nov., sp. nov. and Mechercharimyces asporophorigenens sp. nov., antitumour substance-producing marine bacteria, and description of Thermoactinomycetaceae fam. nov." International Journal of Systematic and Evolutionary Microbiology 56, no. 12 (December 1, 2006): 2837–42. http://dx.doi.org/10.1099/ijs.0.64223-0.

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A study was carried out to clarify the taxonomy of four Gram-positive, heterotrophic mesophiles isolated from marine lakes in the Republic of Palau. The strains, designated YM3-251T, YM3-653, YM3-671 and YM11-542T, formed aerial and substrate mycelia. The cell-wall peptidoglycan contained meso-diaminopimelic acid, glutamic acid and alanine. The G+C content of their genomic DNA was approximately 45 mol%. The major fatty acid was iso-C15 : 0 and the major isoprenoid quinone was MK-9. The strains formed a distinct group in the 16S rRNA gene tree and shared a range of phenotypic properties that distinguished them from members of related genera in Thermoactinomycetaceae fam. nov. The name proposed to accommodate the new isolates is Mechercharimyces gen. nov., comprising two species based on genotypic and phenotypic criteria, including comparative gyrB and DNA–DNA relatedness data. The names proposed for these taxa are Mechercharimyces mesophilus sp. nov., the type species, and Mechercharimyces asporophorigenens sp. nov., with the type strains YM3-251T (=MBIC06230T=DSM 44894T) and YM11-542T (=MBIC06487T=DSM 44955T), respectively.
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20

AL-HOLY, M., M. LIN, and B. RASCO. "Destruction of Listeria monocytogenes in Sturgeon (Acipenser transmontanus) Caviar by a Combination of Nisin with Chemical Antimicrobials or Moderate Heat." Journal of Food Protection 68, no. 3 (March 1, 2005): 512–20. http://dx.doi.org/10.4315/0362-028x-68.3.512.

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The objective of this study was to investigate the effect of nisin in combination with heat or antimicrobial chemical treatments (such as lactic acid, chlorous acid, and sodium hypochlorite) on the inhibition of Listeria monocytogenes and total mesophiles in sturgeon (Acipenser transmontanus) caviar. The effects of nisin (250, 500, 750, and 1,000 IU/ml), lactic acid (1, 2, and 3%), chlorous acid (134 and 268 ppm), sodium hypochlorite (150 and 300 ppm), and heat at 60°C for 3 min were evaluated for a five-strain mixture of L. monocytogenes and total mesophiles in sturgeon caviar containing 3.5% salt. Selected combinations of these antimicrobial treatments were also tested. Injured and viable L. monocytogenes cells were recovered using an overlay method. Treating caviar with ≥500 IU/ml nisin initially reduced L. monocytogenes by 2 to 2.5 log units. Chlorous acid (268 ppm) reduced L. monocytogenes from 7.7 log units to undetectable (&lt;0.48 log units) after 4 days of storage at 4°C. However, there were no synergistic effects observed for combinations of nisin (500 or 750 IU/ml) plus either lactic acid or chlorous acid. Lactic acid caused a slight reduction (~1 log unit) in the microbial load during a 6-day period at 4°C. Sodium hypochlorite was ineffective at the levels tested. Mild heating (60°C for 3 min) with nisin synergistically reduced viable counts of L. monocytogenes and total mesophiles. No L. monocytogenes cells (&lt;0.48 log units) were recovered from caviar treated with heat and nisin (750 IU/ml) after a storage period of 28 days at 4°C.
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Pereira, Elisângela Borsoi, Magali Soares dos Santos Pozza, Paula Martins Olivo, Osmar Dalla Santa, Suzana da Cruz Pires, Joelmir André Borsoi, Patrícia Barcellos Costa, and Paulo Cesar Pozza. "Microbiota indigenous milk, mesophilic lipolytic and proteolytic colonial cheese matured, produced at different times of the year." Revista Brasileira de Saúde e Produção Animal 18, no. 4 (December 2017): 549–59. http://dx.doi.org/10.1590/s1519-99402017000400006.

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SUMMARY Cheese is the oldest form of preserving milk nutrients having nutritional, economic and cultural importance. The objective of this study was to identify the best time of the year for production, and period, in months, for maturation of traditional colonial cheese, through analysis of water activity, weight loss and counts of lactic acid, mesophilic microorganisms—proteolytic and lipolytic. Records of temperature and relative humidity (RH) were maintained. A completely randomized experimental design was used in a double factorial scheme, considering production periods and maturation times. For all production periods evaluated, there was a significant reduction in the periods for water activity values. The counts of lactic acid bacteria ranged from 104 to 109 CFU/g. There was also stability in the number of colonies for lipolytic mesophilic microorganisms, until the third month of maturation. Low counts of proteolytic mesophiles were observed for the samples produced in May and June (5.70 and 5.53 log), respectively. The production period for the months of May and June corresponding to RH of 80% and average temperatures of 15°C were the most effective for production. Due to the presence of Listeria, it is recommended to respect the minimum time of 60 days of maturation for commercialization.
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Schmiedt, Jhennifer Arruda, Leonardo Ereno Tadielo, Thiago Henrique Bellé, Carolina Dias Rodrigues, Maike Tais Maziero Montanhini, Vinicius Cunha Barcellos, and Luciano Dos Santos Bersot. "Influence of time and storage temperature on raw milk deteriorating microbiota." Brazilian Journal of Veterinary Research and Animal Science 57, no. 1 (April 24, 2020): e156883. http://dx.doi.org/10.11606/issn.1678-4456.bjvras.2020.156883.

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The quality of raw milk depends on initial microbial contamination and conditions of storage until industry processing. Considering the influence of time and storage temperature on raw milk microbiota, the objective of this work was to quantify and monitor the multiplication of these groups under different conditions. For this purpose, 41 samples of raw milk were collected immediately after milking, stored in the following storage conditions: 25 °C/2 h; 35 °C/2 h; 7 °C/24 h; 7 °C/48 h and 7 °C/60 h and analyses of aerobic mesophilic, psychrotrophic and proteolytic psychrotrophic microorganisms. The milk samples analyzed in the study had an initial mean count of mesophilic aerobes of 5.38 Log CFU/mL at Time Zero. The milk stored at 25 °C/2 h and 35 °C/2 h kept the mesophilic aerobic counts within the limits established by the legislation (5.48 Log CFU/mL), with an increase in counts of psychrotrophic and proteolytic microorganisms. When stored at 7 °C/24 h and 7 °C/48 h, the count of mesophiles exceeded the established parameters. A significant increase in the count of proteolytic psychrotrophs and psychrotrophs was also observed during storage at 7 °C from 24 h. The results of this study indicate that the temperature of 7 °C is not suitable for the milk conservation, since it was not able to control the microbial multiplication. Thus, the results contribute to the change in milk storage temperature proposed by the new Brazilian legislation.
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Miller, Robert V., Katharine Gammon, and Martin J. Day. "Antibiotic resistance among bacteria isolated from seawater and penguin fecal samples collected near Palmer Station, AntarcticaThis article is one of a selection of papers in the Special Issue on Polar and Alpine Microbiology." Canadian Journal of Microbiology 55, no. 1 (January 2009): 37–45. http://dx.doi.org/10.1139/w08-119.

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Antibiotic resistance in aquatic bacteria has increased steadily as a consequence of the widespread use of antibiotics, but practice and international treaty should have limited antibiotic contamination in Antarctica. We estimated antibiotic resistance in microorganisms isolated from the Antarctic marine waters and a penguin rookery, for 2 reasons: (i) as a measure of human impact and (ii) as a potential “snapshot” of the preantibiotic world. Samples were taken at 4 established sampling sites near Palmer Station, which is situated at the southern end of the Palmer Archipelago (64°10′S, 61°50′W). Sites were chosen to provide different potentials for human contamination. Forty 50 mL samples of seawater were collected and colony-forming units (CFU)/mL were determined at 6 and 20 °C. For this study, presumed psychrophiles (growth at 6 °C) were assumed to be native to Antarctic waters, whereas presumed mesophiles (growth at 20 °C but not at 6 °C) were taken to represent introduced organisms. The 20–6 °C CFU/mL ratio was used as a measure of the relative impact to the ecosystem of presumably introduced organisms. This ratio was highest at the site nearest to Palmer Station and decreased with distance from it, suggesting that human presence has impacted the natural microbial flora of the site. The frequency of resistance to 5 common antibiotics was determined in each group of isolates. Overall drug resistance was higher among the presumed mesophiles than the presumed psychrophiles and increased with proximity to Palmer Station, with the presumed mesophiles showing higher frequencies of single and multiple drug resistance than the psychrophile population. The frequency of multidrug resistance followed the same pattern. It appears that multidrug resistance is low among native Antarctic bacteria but is increased by human habitation.
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Hori, Hiroyuki, Takuya Kawamura, Takako Awai, Anna Ochi, Ryota Yamagami, Chie Tomikawa, and Akira Hirata. "Transfer RNA Modification Enzymes from Thermophiles and Their Modified Nucleosides in tRNA." Microorganisms 6, no. 4 (October 20, 2018): 110. http://dx.doi.org/10.3390/microorganisms6040110.

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To date, numerous modified nucleosides in tRNA as well as tRNA modification enzymes have been identified not only in thermophiles but also in mesophiles. Because most modified nucleosides in tRNA from thermophiles are common to those in tRNA from mesophiles, they are considered to work essentially in steps of protein synthesis at high temperatures. At high temperatures, the structure of unmodified tRNA will be disrupted. Therefore, thermophiles must possess strategies to stabilize tRNA structures. To this end, several thermophile-specific modified nucleosides in tRNA have been identified. Other factors such as RNA-binding proteins and polyamines contribute to the stability of tRNA at high temperatures. Thermus thermophilus, which is an extreme-thermophilic eubacterium, can adapt its protein synthesis system in response to temperature changes via the network of modified nucleosides in tRNA and tRNA modification enzymes. Notably, tRNA modification enzymes from thermophiles are very stable. Therefore, they have been utilized for biochemical and structural studies. In the future, thermostable tRNA modification enzymes may be useful as biotechnology tools and may be utilized for medical science.
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Hernández-Carranza, Paola, Arely Peralta-Pérez, Raúl Avila-Sosa, Irving Israel Ruiz-López, Alfredo C. Benitez-Rojas, and Carlos Enrique Ochoa-Velasco. "Effect of ultraviolet-C light and mild thermal treatment on the storage life of orange juice." Czech Journal of Food Sciences 39, No. 2 (April 29, 2021): 106–12. http://dx.doi.org/10.17221/21/2020-cjfs.

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This study aimed to evaluate the effect of low-dosage treatment with ultraviolet-C light (19.75 J L<sup>–1</sup> for 5 min), mild thermal treatment (40 °C for 5 min), or their combination on the native microflora (mesophiles and moulds plus yeast) and consumer acceptance of orange juice at the beginning and after storage (5 or 22 °C). Results indicated that UV-C light and mild thermal treatments reduce 0.19 ± 0.03 and 0.25 ± 0.02 log cycles (both kinds of microorganisms), respectively. The combination of treatments displays an additive effect against mesophiles (0.47 ± 0.01 log) and moulds plus yeasts (0.42 ± 0.02 log). After 9 days of storage at 5 °C, combined treatment did not present any microbial increases (P &gt; 0.05), while consumer acceptance was similar (P &gt; 0.05) to the fresh orange juice. Although several studies about the use of hurdle technology using UV-C light in orange juice have to be conducted, the results obtained in this study are promising, and they can be used for further studies.
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Georgiev, Plamen, Irena Spasova, Veneta Groudeva, Marina Nicolova, Albena Lazarova, Michail Iliev, Ralitca Ilieva, and Stoyan Groudev. "Bioleaching of Valuable Components from a Pyrometallurgical Final Slag." Solid State Phenomena 262 (August 2017): 696–99. http://dx.doi.org/10.4028/www.scientific.net/ssp.262.696.

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Pyrometallurgical copper final slag was subjected to leaching by means microbial cultures of three different groups based on their optimum temperature for growth and activity: mesophilic and moderate thermophilic bacteria, and extreme thermophilic archaea. The leaching experiments were performed by the shake-flask technique and in agitated bioreactors under batch and continuous-flow conditions. The effect of the most essential factors (particle size, pulp density, pH, aeration) on this process was studied. The highest rates of extraction of the non-ferrous metals (Cu, Zn, Co) and iron were achieved by means of some archaea but at relatively low pulp densities (5 – 10%). Some moderate thermophilic bacteria were the most efficient at the higher pulp densities (15 – 20 %). The, leaching by some mesophiles at pH 3.0 – 3.5 was also very attractive since it was connected with high extractions of these metals (about 85 – 92% at 20% pulp density), much lower acid consumption and low solubiliation of fayalite which resulted in the production of pregnant solutions suitable for the recovery of the dissolved non-ferrous metals.
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LI, KEN-YUON, and J. ANTONIO TORRES. "Water Activity Relationships for Selected Mesophiles and Psychrotrophs at Refrigeration Temperature." Journal of Food Protection 56, no. 7 (July 1, 1993): 612–15. http://dx.doi.org/10.4315/0362-028x-56.7.612.

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The growth rate and lag phase of Pseudomonas fluorescens, Brochothrix thermosphacta, Salmonella typhlmurium, Enterococcus faecalis, and Staphylococcus aureus were studied in liquid media as a function of temperature, water activity (aw) and solute type. The lag phase lengthened and the growth rate decreased when the temperature was lowered or the aw reduced, and these variations depended on the aw-controlling solute. In general, the magnitude order of the solute effect on the growth rate parameters was glycerol &lt; NaCl &lt; sucrose. This effect can be related to the ability of the solutes to permeate the cell and can be explained by the osmoregulatory mechanism. The specific growth rate was not as sensitive to the aw-controlling solute as the lag phase. A linear extrapolation method was a reliable and convenient method to estimate the minimum aw for microbial growth.
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Valenti, Anna, Giuseppe Perugino, Mosè Rossi, and Maria Ciaramella. "Positive supercoiling in thermophiles and mesophiles: of the good and evil." Biochemical Society Transactions 39, no. 1 (January 19, 2011): 58–63. http://dx.doi.org/10.1042/bst0390058.

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DNA supercoiling plays essential role in maintaining proper chromosome structure, as well as the equilibrium between genome dynamics and stability under specific physicochemical and physiological conditions. In mesophilic organisms, DNA is negatively supercoiled and, until recently, positive supercoiling was considered a peculiar mark of (hyper)thermophilic archaea needed to survive high temperatures. However, several lines of evidence suggest that negative and positive supercoiling might coexist in both (hyper)thermophilic and mesophilic organisms, raising the possibility that positive supercoiling might serve as a regulator of various cellular events, such as chromosome condensation, gene expression, mitosis, sister chromatid cohesion, centromere identity and telomere homoeostasis.
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BAI, YONG, LESTER A. WILSON, and BONITA A. GLATZ. "Quality of Commercial Shelf-Stable Soymilk Products†." Journal of Food Protection 61, no. 9 (September 1, 1998): 1161–64. http://dx.doi.org/10.4315/0362-028x-61.9.1161.

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Four brands of shelf-stable soymilks (three lots each) were evaluated for their quality. All samples were tested for trypsin inhibitor activity, microbial load (coliforms, aerobio mesophiles, and psychrotrophs), solids content, pH, color, and viscosity. Storage stability at 5°C of the opened original containers was evaluated by microbiological analyses. Physical properties were consistent among three lots of the same brand, but varied among brands. Trypsin inhibitor activity ranged from 3.43 to 10.35 mg/g dried soymilk. The pH values of the soymilks varied between 6.41 and 7.34. Viscosity was measured between 16.5 and 26.4 mPa. Solids content varied considerably among soymilks, from 6.88 to 12.37% (wt/vol). Freshly opened commercial soymilk contained fewer than one microorganism per ml in all microbial counts. During storage at 5°C, microbial counts increased sharply after 2 to 3 weeks. A single microorganism predominated in each stored sample. Shelf life (defined as the time during which aerobio mesophile counts remained below 106 CFU/ml) varied from 3 to 4 weeks. The appearance and pH of soymilks remained unchanged even after 4 weeks of storage. Five types of microorganisms were found in stored soymilk samples; none of them produced acid.
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CARR, T. P., and J. A. MARCHELLO. "Microbial Changes of Precooked Beef Slices as Affected by Packaging Procedure." Journal of Food Protection 49, no. 7 (July 1, 1986): 534–36. http://dx.doi.org/10.4315/0362-028x-49.7.534.

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Precooked beef slices from top round roasts were used in replicate trials to determine the effects of packaging treatment upon microbial growth during retail storage. Roasts were dry roasted to an internal temperature of 60°C, cooled for 1 h, then sliced (3 to 4 mm) and packaged in vacuum or an atmosphere containing 15% CO2/40% O2/45% N2. Slices were stored either at 2, 6 or 10°C for up to 21 d. Enumeration of psychrotrophs, mesophiles, thermophiles and molds was determined after 0, 7, 14 and 21 d of storage. At 6 and 10°C storage, psychrotrophic organisms did not increase (P&lt;0.05) on vacuum packaged beef slices during the 21-d storage period, but did increase (P&lt;0.05) on slices stored in the gas mixture. Conversely, at 2°C storage, psychrotrophs increased (P&lt;0.05) in vacuum at day 21 but not under gas atmosphere storage. Mesophiles did not increase significantly at 2 or 6°C storage within either packaging treatment during 21 d of storage. Mold growth did not occur on slices stored at 2°C.
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Bermúdez-Aguirre, D., J. Ángel Guerrero-Beltrán, G. V. Barbosa-Cánovas, and J. Welti-Chanes. "Study of the inactivation of Escherichia coli and pectin methylesterase in mango nectar under selected high hydrostatic pressure treatments." Food Science and Technology International 17, no. 6 (November 2, 2011): 541–47. http://dx.doi.org/10.1177/1082013211399681.

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High hydrostatic pressure (HHP) was applied to fresh mango nectar (FMN) and sterilized mango nectar (SMN) to inactivate Escherichia coli and pectin methylesterase (PME). Pressure was applied at 275, 345 and 414 MPa. The come-up time (CUT) as well as 1, 2 and 4 min of treatment times were applied at the selected pressure to evaluate the inactivation effect on E. coli and PME. Total plate counts (TPC) were also evaluated in FMN. Results showed that mesophiles are inactivated in FMN to an important degree (up to 4 log) only with the CUT; the highest inactivation for mesophiles (7 log) was reported at 414 MPa after 4 min. Meanwhile, for E. coli 345 and 414 MPa after 2 and 1 min, respectively, were able to inactivate all viable cells in FMN. However, in SMN after 4 min at 275 MPa all cells of E. coli were also inactivated, showing the protective effect of the media between FMN and SMN. The PME showed its resistance to be inactivated with high pressure, showing the highest decrease in enzymatic activity (45%) after 4 min at 345 MPa but with an important activation at the highest pressure (414 MPa).
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Ferriccioni, Natalia, Ricardo Mateucci, Agustina Zangrando, Susana Santana, and Carmen A. Campos. "Effect of decontamination treatment on the quality of dehydrated thyme, coriander, and mustard." Food Science and Technology International 25, no. 7 (May 22, 2019): 579–87. http://dx.doi.org/10.1177/1082013219850667.

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The objective of this work was to evaluate the effects of different decontamination treatments on the quality of dehydrated thyme, coriander, and mustard. Treatments applied were: (i) ultraviolet radiation treatment irradiation; (ii) steam, (iii) steam–ultraviolet radiation treatment; (iv) humidification–ultraviolet radiation treatment, and (v) steam–humidification–ultraviolet radiation treatment. Their effectiveness to control indigenous aerobic mesophiles and yeasts and molds population was assessed by plate count. The effect of proposed treatments on total polyphenol contents and antioxidant activity was also evaluated. Furthermore, the effect of treatments on spices performance to prevent canola oil oxidation was also analyzed. The use of steam–ultraviolet radiation treatment in aqueous medium was the most effective for decontamination, reducing the aerobic mesophiles and yeasts and molds counts between 1.0 and 2.2 log CFU/g dry spice. This treatment decreased significantly the polyphenol content and the antioxidant capacity of the three spices analyzed. However, in the case of mustard, the residual antioxidant compounds were able to control canola oil oxidation more efficiently than butylated hydroxytoluene. Results suggest that the use of steam–ultraviolet radiation treatment in aqueous medium can be useful in food preservation processes.
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Horvitz, Sandra, Mirari Arancibia, Cristina Arroqui, Erika Chonata, and Paloma Vírseda. "Effects of Gaseous Ozone on Microbiological Quality of Andean Blackberries (Rubus glaucus Benth)." Foods 10, no. 9 (August 30, 2021): 2039. http://dx.doi.org/10.3390/foods10092039.

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Andean blackberries are highly perishable due to their susceptibility to water loss, softening, mechanical injuries, and postharvest diseases. In this study, the antimicrobial efficacy of gaseous ozone against spoilage (mesophiles, psychrotrophs, and yeasts and molds) and pathogenic (E. coli, S. enterica, and B. cinerea) microorganisms was evaluated during 10 days of storage at 6 ± 1 °C. Respiration rate and mass loss were also determined. Ozone was applied prior to storage at 0.4, 0.5, 0.6, and 0.7 ppm, for 3 min. The best results were observed with the higher ozone dose, with initial maximum reductions of ~0.5, 1.09, and 0.46 log units for E. coli, S. enterica, and B. cinerea, respectively. For the native microflora, maximum reductions of 1.85, 1.89, and 2.24 log units were achieved on day 1 for the mesophiles, psychrotrophs, and yeasts and molds, respectively, and this effect was maintained throughout storage. In addition, the lower respiration rate and mass loss of the blackberries ozonated at 0.7 ppm indicate that this treatment did not induce physiological damage to the fruit. Gaseous O3 could be effective in maintaining the postharvest quality of blackberries throughout refrigerated storage but higher doses could be advisable to enhance its antimicrobial activity.
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Coelho-Fernandes, Sara, Odete Zefanias, Gisela Rodrigues, Ana Sofia Faria, Ângela Fernandes, Lillian Barros, Vasco Cadavez, and Ursula Gonzales-Barron. "Microbiological and Physicochemical Assessment of Artisanally Produced “Alheira” Fermented Sausages in Northern Portugal." Proceedings 70, no. 1 (November 9, 2020): 16. http://dx.doi.org/10.3390/foods_2020-07627.

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Alheira is a traditional non-ready-to-eat sausage produced mainly in northern Portugal. The objective of this study was to evaluate the associations between some relevant physicochemical and microbiological attributes of alheiras produced by different regional producers. Finished products from 8 regional factories amounting to 40 samples were analyzed. Counts of mesophiles, lactic acid bacteria, Staphylococcus aureus, presumptive Clostridium perfringens, and Salmonella spp., as well as pH, water activity (aW), and proximate analysis were determined. Principal component analysis (PCA) of these variables was conducted to construct quality maps. Three meaningful components were extracted, accounting for 63% of data variability. PC1 (26% data variability) was positively associated with LAB, mesophiles, and S. aureus, characterizing therefore longer fermentation. PC2 (22% data variability) correlated negatively with moisture, aW and positively with C. perfringens, and thus has been linked to greater dehydration of sausages. PC3 (15% data variability) correlated positively with pH and protein content, implying the use of more meat in the formulation. This preliminary work has identified three quality factors underpinning the variability in artisanal alheiras; and has also highlighted the need to implement better microbiological control and process standardization during the production of artisanal alheiras.
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Banerjee, Shyamashree. "Comparison of evolutionary characteristics of orthologous sets from halophiles, thermophiles and mesophiles." IOSR Journal of Pharmacy and Biological Sciences 9, no. 5 (2014): 01–06. http://dx.doi.org/10.9790/3008-09560106.

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Ogawa, Umi, Kento Koyama, and Shigenobu Koseki. "Rapid detection and enumeration of aerobic mesophiles in raw foods using dielectrophoresis." Journal of Microbiological Methods 186 (July 2021): 106251. http://dx.doi.org/10.1016/j.mimet.2021.106251.

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37

Martins, Pedro Alves, and Héberly Fernandes Braga. "Monitoramento da Qualidade Microbiológica Ambiental em Unidade de Alimentação." UNICIÊNCIAS 23, no. 2 (December 4, 2019): 115. http://dx.doi.org/10.17921/1415-5141.2019v23n2p115-120.

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Restaurantes podem propiciar doenças veiculadas por alimentos, assim, medidas de controle devem ser realizadas. Objetivou-se quantificar coliformes totais, termotolerantes e bactérias heterotróficas mesófilas na superfície da bancada da pia de manipulação, e bioaerossóis fúngicos em unidade de alimentação em uma instituição de ensino, antes e durante o processamento dos alimentos, e após higienização do local de trabalho. As amostras foram colhidas por swab e o ar, pela exposição, durante 15 minutos, de placas de PDA acidificado, em diferentes dias da semana totalizando dezesseis coletas. Coliformes totais (35 ºC, 24/48 h) e termotolerantes (45 ºC, 24 h) foram quantificados por inoculação de diluições seriadas, em caldo VB e EC, respectivamente, e os resultados expressos em NMP/cm2. A contagem de mesófilos (35 °C, 48 h) foi realizada em ágar PCA, e os resultados expressos em UFC/cm2. Os fungos anemófilos cultivados a 25 ºC por sete dias foram expressos em UFC/15 min. Os resultados foram analisados em software ASSISTAT 7.6 betas. Foi verificada contagem > 103NMP/cm2 para coliformes totais durante o processamento, e após higienização, decaimento de 16% em relação à média inicial. Redução de 56,3% foi observada para coliformes termotolerantes. O número de mesófilos se mantiveram ≥ 3 ciclos log, independentemente, do período da coleta (antes, durante ou após processamento). 54,2% das amostras do ar apresentaram altas contagens para fungos (> 50 UFC/15 min.). Os resultados indicam a possível geração de riscos e ocorrência de toxinfecções alimentares. Quando bem realizada, a higienização é eficaz na redução da carga microbiana. Sugere-se melhor monitoramento dos procedimentos realizados pelos manipuladores. Palavras-chave: Aerossóis. Coliformes. Mesófilos. AbstractRestaurants can provide food-borne diseases, so control measures must be taken. The objective of this study was to quantify total coliforms, thermotolerant bacteria and mesophilic heterotrophic bacteria on the sink basin surface, and fungal bioaerosols in a feeding unit at a teaching institution, before and during food processing, and after cleaning the workplace. Samples were collected by swab and air by exposure for 15 minutes of acidified PDA plates on different days of the week totaling sixteen samples. Total (35°C, 24/48 h) and thermotolerant coliforms (45 °C, 24 h) were quantified by inoculation of serial dilutions in VB and EC broth, respectively, and the results expressed as MLN/cm2. The counts of mesophiles (35 °C, 48 h) were performed on PCA agar and the results expressed in CFU/cm2. Anemophilous fungi cultured at 25°C for seven days were expressed in CFU/15 min. The results were analyzed in ASSISTAT 7.6 betas software. It was verified a count > 103 MLN/cm2 for total coliforms during the processing, and after sanitization, decay of 16% in relation to the initial average. Reduction of 56.3% was observed for thermotolerant coliforms. The number of mesophiles remained ≥ 3 log cycles, regardless of the collection period (before, during or after processing). 54.2% of the air samples had high counts for fungi (> 50 CFU/15 min). The results indicate the possible generation of risks and occurrence of alimentary toxinfections. When properly performed, hygiene is effective in reducing microbial load. It is suggested better procedures monitoring performed by the handlers. Keywords: Aerosols. Coliforms. Mesophiles.
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Pérez-Soto, Elizabeth, Antonio de Jesús Cenobio-Galindo, Salvador Omar Espino-Manzano, Melitón Jesús Franco-Fernández, Fanny Emma Ludeña-Urquizo, Rubén Jiménez-Alvarado, Andrea Paloma Zepeda-Velázquez, and Rafael Germán Campos-Montiel. "The Addition of Microencapsulated or Nanoemulsified Bioactive Compounds Influences the Antioxidant and Antimicrobial Activities of a Fresh Cheese." Molecules 26, no. 8 (April 9, 2021): 2170. http://dx.doi.org/10.3390/molecules26082170.

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The objective of this study was to compare the effects of the incorporation of microcapsules or nanoemulsions with Opuntiaoligacantha on the quality of fresh cheese. Three treatments were established: Control, cheese with microcapsules (Micro), and cheese with nanoemulsion (Nano). The parameters evaluated were physicochemical (moisture, ash, fat, proteins, and pH), microbiological (mesophilic aerobic bacteria, mold–yeast, and total coliforms), functional (total phenols, flavonoids, and antioxidant capacity), and texture (hardness, elasticity, cohesion, and chewiness) during storage for 45 days at 4 °C. The results showed that adding microcapsules and nanoemulsion did not affect the physicochemical parameters of the cheese. Total coliforms decreased in all samples from the first days of storage (Control: 4.23 ± 0.12, Micro: 3.27 ± 0.02, and Nano: 2.68 ± 0.08 Log10 CFU), as well as aerobic mesophiles and mold–yeast counts. Regarding the functional properties, an increase in total phenols was observed in all treatments. The texture profile analysis showed that the addition of microcapsules and nanoemulsion influenced hardness (Control: 8.60 ± 1.12, Micro: 1.61 ± 0.31, and Nano: 3.27 ± 0.37 N). The antimicrobial effect was greater when nanoemulsions were added, while adding microcapsules influenced the antioxidant activity more positively.
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Rodrigues, Laura Beatriz, Luciana Ruschel Dos Santos, Natalie Nadin Rizzo, Daiane Ferreira, Amauri Picollo De Oliveira, Rafael Levandowski, Bruna Webber, and Vladimir Pinheiro Do Nascimento. "ATP-Bioluminescence and Conventional Microbiology for Hygiene Evaluation of Cutting Room Surfaces in Poultry Slaughterhouse." Acta Scientiae Veterinariae 46, no. 1 (March 4, 2018): 6. http://dx.doi.org/10.22456/1679-9216.86204.

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Background: The hygiene procedures in poultry slaughterhouses consist in the use of hot water, detergent and sanitizing, configuring Sanitation Standard Operating Procedure (SSOP). These actions control contamination in food processing environments, especially by pathogenic microorganisms, which cause diseases with impact on public health and economic losses. The microbiological control of aerobic mesophiles, Staphylococcus aureus and Escherichia coli, are used as indicators of contamination. The hygienic-sanitary conditions on the surfaces of the poultry slaughterhouse cuttting room were evaluated, before and after cleaning and sanitizing procedures.Materials, Methods & Results: Conventional microbiology (Rodac plates and sponge for quantification of aerobic mesophiles, Staphylococcus aureus and Escherichia coli) and ATP-Bioluminescence were used to analyze the action of hot water and the active principles peracetic acid, quaternary ammonia and biguanide in the standard pre-operational hygiene procedure in the cutting room of the poultry slaughterhouse under Federal Inspection with slaughter capacity of more than 20.000 birds/h. The evaluations were performed on three lines of chicken thigh cuts at the same time and in a completely randomized manner on stainless steel surfaces, polyurethane belts and polyethylene boards. Samples were made in four replicates at the three surface totaling 108 assay for each microorganism. The samples were collected at the end of the cuttingprocess, before and after washing the surfaces with hot water (between 45 and 50ºC) and after sanitization with 0.5% peracetic acid, 2% quaternary ammonia and 1% biguanide. The ATP-Bioluminescence method detected organic matter at all collected points and Rodac plates allowed a better recovery of microorganisms than sponges for quantification of aerobic mesophiles, E. coli and S. aureus. There was a reduction of contamination after the action of hot water and, after using quaternary ammonia and peracetic acid, there was no isolation of E. coli and S. aureus on all evaluated surfaces.Discussion: The use of different methods of analysis for monitoring the hygiene and sanitary status of contact surfaces with chicken cuts allows greater flexibility in relation to hygiene control. The use of the bioluminescent ATP detection method allows detecting in seconds extremely low levels of contamination, allowing a quick determination of the cleaning efficiency on the surfaces and evaluation of the hygiene programs. Conventional microbiology methods, on the other hand, provideindicators of contamination by different microorganisms on food contact surfaces. Both are applicable in SSOP monitoring programs and sanitary conditions of the contact surfaces in food producing establishments. The significant reduction of microorganisms on surfaces after cleaning, found in this study, demonstrates the importance of operational hygiene inthe maintenance of microbial contamination below the recommended limits, and to reconcile the ATP-Bioluminescence methodologies and Rodac plates can bring benefits to the control of this contamination, and the use of ATP-bioluminescence makes possible taking immediate corrective measures after the evaluation of sanitation procedures.Keywords: ATP-Bioluminescence, Rodac plates, Escherichia coli, mesophiles, Staphylococcus aureus.
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Reeve, J. N., K. A. Bailey, W.-t. Li, F. Marc, K. Sandman, and D. J. Soares. "Archaeal histones: structures, stability and DNA binding." Biochemical Society Transactions 32, no. 2 (April 1, 2004): 227–30. http://dx.doi.org/10.1042/bst0320227.

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Structures, stability and DNA-binding properties have been established for archaeal histones from mesophiles, thermophiles and hyperthermophiles. Most archaeal histones are simply histone folds that are stabilized by dimer formation. Archaeal histones and the histone folds of the eukaryotic nucleosome core histones share a common ancestry and bind and wrap DNA similarly using conserved residues. The histone-fold residues that stabilize dimer–dimer interactions within an archaeal histone core contribute to determining archaeal histone–DNA affinity.
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41

ÖZDEMIR, A., H. KOCAYIGIT, K. YETISEN, Y. AKYOL, and C. ÖZDEMIR. "A STATISTICAL COMPARISON OF ANATOMICAL FEATURES IN SOME Ornithogalum SP. SPECIES." Planta Daninha 34, no. 3 (September 2016): 485–95. http://dx.doi.org/10.1590/s0100-83582016340300009.

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ABSTRACT In the present study, Ornithogalum narbonense, O. montanum, O. wiedemannii, O. sigmoideum and O. lanceolatum species were compared statistically with respect to anatomical characters. Some differences were found in root, stem and leaf anatomy of the species. These differences and similarities were indicated in this study. A big metaxylem was present in all root cross sections, except for O. lanceolatum, which has three metaxylema. 2-3 layered annular type collenchyma were present in all species. Aerenchyma is present in all mesophiles.
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42

Baker, P. J. "From hyperthermophiles to psychrophiles: the structural basis of temperature stability of the amino acid dehydrogenases." Biochemical Society Transactions 32, no. 2 (April 1, 2004): 264–68. http://dx.doi.org/10.1042/bst0320264.

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The determination and comparison of the structures of a number of glutamate dehydrogenases that span the spectrum of thermal stability from mesophiles to hyperthermophiles have revealed that the formation of extended ion-pair networks is a major stabilizing feature in the adaptation of the organism to life at 100°C. Analysis of the structures of other hyperthermophilic proteins has shown that ion-pair networks also play roles in their stabilization, including the phosphoglucose isomerase from Pyrococcus furiosus and the maltosyltransferase from Thermotoga maritima.
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43

Munsch-Alatossava, Patricia, Oguz Gursoy, and Tapani Alatossava. "Potential of nitrogen gas (N2) to control psychrotrophs and mesophiles in raw milk." Microbiological Research 165, no. 2 (February 2010): 122–32. http://dx.doi.org/10.1016/j.micres.2009.02.002.

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44

López-García, P., and P. Forterre. "DNA topology and the thermal stress response, a tale from mesophiles and hyperthermophiles." Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 126 (July 2000): 96. http://dx.doi.org/10.1016/s1095-6433(00)80190-7.

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45

Huang, Qi, Jocelyn M. Rodgers, Russell J. Hemley, and Toshiko Ichiye. "Quasiharmonic Analysis of the Energy Landscapes of Dihydrofolate Reductase from Piezophiles and Mesophiles." Journal of Physical Chemistry B 122, no. 21 (January 25, 2018): 5527–33. http://dx.doi.org/10.1021/acs.jpcb.7b11838.

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46

López-García, Purificación, and Patrick Forterre. "DNA topology and the thermal stress response, a tale from mesophiles and hyperthermophiles." BioEssays 22, no. 8 (July 24, 2000): 738–46. http://dx.doi.org/10.1002/1521-1878(200008)22:8<738::aid-bies7>3.0.co;2-5.

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47

Pancsa, Rita, Denes Kovacs, and Peter Tompa. "Misprediction of Structural Disorder in Halophiles." Molecules 24, no. 3 (January 29, 2019): 479. http://dx.doi.org/10.3390/molecules24030479.

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Whereas the concept of intrinsic disorder derives from biophysical observations of the lack of structure of proteins or protein regions under native conditions, many of our respective concepts rest on proteome-scale bioinformatics predictions. It is established that most predictors work reliably on proteins commonly encountered, but it is often neglected that we know very little about their performance on proteins of microorganisms that thrive in environments of extreme temperature, pH, or salt concentration, which may cause adaptive sequence composition bias. To address this issue, we predicted structural disorder for the complete proteomes of different extremophile groups by popular prediction methods and compared them to those of the reference mesophilic group. While significant deviations from mesophiles could be explained by a lack or gain of disordered regions in hyperthermophiles and radiotolerants, respectively, we found systematic overprediction in the case of halophiles. Additionally, examples were collected from the Protein Data Bank (PDB) to demonstrate misprediction and to help understand the underlying biophysical principles, i.e., halophilic proteins maintain a highly acidic and hydrophilic surface to avoid aggregation in high salt conditions. Although sparseness of data on disordered proteins from extremophiles precludes the development of dedicated general predictors, we do formulate recommendations for how to address their disorder with current bioinformatics tools.
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Vásquez García, A., S. H. Gomes de Sá, G. de Sousa Silva, J. E. Mejia Ballesteros, E. Barbieri, R. L. Moro de Sousa, A. M. Fernandes, and M. Mitsui Kushida. "Microbiological quality of shellfish and evaluation of compact dry EC for detecting total coliforms and Escherichia coli." Acta Alimentaria 49, no. 1 (March 2020): 32–39. http://dx.doi.org/10.1556/066.2020.49.1.5.

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The objective of this study was to evaluate the microbiological quality of oysters and mussels grown in Cananéia, Brazil, by analysing mesophiles, psychrothophic bacteria, moulds and yeasts, Staphylococcus aureus, and Salmonella spp., and to compare the efficiency of Compact Dry EC method and the conventional method for counting of total coliforms and Escherichia coli. The microbial analysis showed that the mean values of mesophilic counts were 3.14±0.81 log CFU g−1 for oysters and 3.92±0.90 for mussels; the mean values of psychrophilic counts were 2.78±0.75 log CFU g−1 for oysters and 3.22±0.75 log CFU g−1 for mussels; the mean values of mould and yeast counts were 3.70±0.58 log CFU g−1 for oysters and 3.33±0.81 log CFU g−1 for mussels. Salmonella spp. did not present positive results, and the maximal count of Staphylococcus aureus was 1.7 log CFU g−1, therefore, within the limits established in the legislation. The correlation coefficients between the Compact Dry EC method and conventional method were >0.87 for total coliform and E. coli counts for both types of shellfish. The data in this study show that the Compact Dry EC method is an acceptable alternative to conventional methods for enumeration of total coliforms and E. coli in shellfish.
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Bharadwaj, Abhilasha, and Yen Peng Ting. "Bioleaching of Spent Hydrotreating Catalyst by Thermophilic and Mesophilic Acidophiles: Effect of Decoking." Advanced Materials Research 825 (October 2013): 280–83. http://dx.doi.org/10.4028/www.scientific.net/amr.825.280.

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Spent hydrotreating catalyst is a major solid waste from the petroleum industry. Although bioleaching of these wastes has been reported, research to date has focused on mesophiles. Bioleaching of industrial wastes by thermophiles has not been investigated. The bioleaching ability of thermophilic archaea Acidianus brierleyi was examined and compared with the commonly used mesophile Acidithiobacillus thiooxidans to establish the potential for high temperature leaching of spent catalyst. Spent Ni-Mo catalyst embedded in an alumina matrix containing substantial amounts of coke (i.e. carbonaceous deposits and volatile foulants) was used in this study. Decoking (i.e. removal of these deposits) as a pre-treatment and its effect on the leaching characteristics were examined. Spent catalyst is considered a hazardous waste since the toxic metal concentration exceeded the regulatory limit for land disposal and failed the toxicity characteristic leaching procedure (TCLP) test. Bioleaching with A. brierleyi and At. thiooxidans reduced the heavy metal leachate concentration to below regulated levels for safe waste disposal. Leaching efficiencies of 31% Al, 65% Ni and 44% Mo were achieved for coked catalyst using spent medium from At. thiooxidans. With decoked catalyst and spent medium from A. brierleyi, higher leaching efficiencies of 76% Al, 98% Ni and 93% Mo were attained. These results demonstrate the feasibility and the higher efficacy of spent medium leaching of decoked catalyst by acidophilic thermophiles.
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50

Reid, I. N., W. B. Sparks, S. Lubow, M. McGrath, M. Livio, J. Valenti, K. R. Sowers, et al. "Terrestrial models for extraterrestrial life: methanogens and halophiles at Martian temperatures." International Journal of Astrobiology 5, no. 2 (April 2006): 89–97. http://dx.doi.org/10.1017/s1473550406002916.

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Cold environments are common throughout the Galaxy. We are conducting a series of experiments designed to probe the low-temperature limits for growth in selected methanogenic and halophilic Archaea. This paper presents initial results for two mesophiles, a methanogen, Methanosarcina acetivorans, and a halophile, Halobacterium sp. NRC-1, and for two Antarctic cold-adapted Archaea, a methanogen, Methanococcoides burtonii, and a halophile, Halorubrum lacusprofundi. Neither mesophile is active at temperatures below 5 °C, but both cold-adapted microorganisms show significant growth at sub-zero temperatures (−2 °C and −1 °C, respectively), extending previous low-temperature limits for both species by 4–5 °C. At low temperatures, both H. lacusprofundi and M. burtonii form multicellular aggregates, which appear to be embedded in extracellular polymeric substances. This is the first detection of this phenomenon in Antarctic species of Archaea at cold temperatures. The low-temperature limits for both psychrophilic species fall within the temperature range experienced on present-day Mars and could permit survival and growth, particularly in sub-surface environments. We also discuss the results of our experiments in the context of known exoplanet systems, several of which include planets that intersect the Habitable Zone. In most cases, those planets follow orbits with significant eccentricity, leading to substantial temperature excursions. However, a handful of the known gas giant exoplanets could potentially harbour habitable terrestrial moons.
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