Relevant bibliographies by topics / Volatile fatty acids; Thermophil; methanogenic

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters

Academic literature on the topic 'Volatile fatty acids; Thermophil; methanogenic'

Author: Grafiati
Published: 4 June 2021
Last updated: 15 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Volatile fatty acids; Thermophil; methanogenic.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Volatile fatty acids; Thermophil; methanogenic"

1

Hori, Tomoyuki, Shin Haruta, Yoshiyuki Ueno, Masaharu Ishii, and Yasuo Igarashi. "Dynamic Transition of a Methanogenic Population in Response to the Concentration of Volatile Fatty Acids in a Thermophilic Anaerobic Digester." Applied and Environmental Microbiology 72, no. 2 (2006): 1623–30. http://dx.doi.org/10.1128/aem.72.2.1623-1630.2006.

Full text
Abstract:
ABSTRACT In this study, the microbial community succession in a thermophilic methanogenic bioreactor under deteriorative and stable conditions that were induced by acidification and neutralization, respectively, was investigated using PCR-mediated single-strand conformation polymorphism (SSCP) based on the 16S rRNA gene, quantitative PCR, and fluorescence in situ hybridization (FISH). The SSCP analysis indicated that the archaeal community structure was closely correlated with the volatile fatty acid (VFA) concentration, while the bacterial population was impacted by pH. The archaeal community consisted mainly of two species of hydrogenotrophic methanogen (i.e., a Methanoculleus sp. and a Methanothermobacter sp.) and one species of aceticlastic methanogen (i.e., a Methanosarcina sp.). The quantitative PCR of the 16S rRNA gene from each methanogen revealed that the Methanoculleus sp. predominated among the methanogens during operation under stable conditions in the absence of VFAs. Accumulation of VFAs induced a dynamic transition of hydrogenotrophic methanogens, and in particular, a drastic change (i.e., an approximately 10,000-fold increase) in the amount of the 16S rRNA gene from the Methanothermobacter sp. The predominance of the one species of hydrogenotrophic methanogen was replaced by that of the other in response to the VFA concentration, suggesting that the dissolved hydrogen concentration played a decisive role in the predominance. The hydrogenotrophic methanogens existed close to bacteria in aggregates, and a transition of the associated bacteria was also observed by FISH analyses. The degradation of acetate accumulated during operation under deteriorative conditions was concomitant with the selective proliferation of the Methanosarcina sp., indicating effective acetate degradation by the aceticlastic methanogen. The simple methanogenic population in the thermophilic anaerobic digester significantly responded to the environmental conditions, especially to the concentration of VFAs.
APA, Harvard, Vancouver, ISO, and other styles
2

Wilson, C. A., S. M. Murthy, Y. Fang, and J. T. Novak. "The effect of temperature on the performance and stability of thermophilic anaerobic digestion." Water Science and Technology 57, no. 2 (2008): 297–304. http://dx.doi.org/10.2166/wst.2008.027.

Full text
Abstract:
Sustainable operation of an anaerobic sewage sludge digester requires the effective shuttling of carbon from complex organic material to methane gas. The accumulation of intermediates and metabolic products such as volatile fatty acids and hydrogen gas not only reveal inefficiency within the digestion process, but can be detrimental to reactor operation at sufficiently high levels. Eight anaerobic digesters (1 mesophilic and 7 thermophilic) were operated in order to determine the effect of steady-state digestion temperature on the operational stability and performance of the digestion process. Replicate reactors operated at 57.5 °C, the highest temperature studied, were prone to accumulation of volatile fatty acids (4052 and 3411 mg/L as acetate) and gaseous hydrogen. Reactors operated at or below 55 °C showed no such accumulation of intermediate metabolites. Overall methanogenesis was also greatly reduced at 57.5 °C (0.09 L CH4/g VS fed) versus optimal methane formation at 53 °C (0.40 L CH4/g VS fed). Microbial community assessment and free energy calculations suggest that the accumulation of fatty acids and hydrogen, and relatively poor methanogenic performance at 57.5 °C are likely due to temperature limitations of thermophilic aceticlastic methanogens.
APA, Harvard, Vancouver, ISO, and other styles
3

David, Aditi, Tanvi Govil, Abhilash Tripathi, Julie McGeary, Kylie Farrar, and Rajesh Sani. "Thermophilic Anaerobic Digestion: Enhanced and Sustainable Methane Production from Co-Digestion of Food and Lignocellulosic Wastes." Energies 11, no. 8 (2018): 2058. http://dx.doi.org/10.3390/en11082058.

Full text
Abstract:
This article aims to study the codigestion of food waste (FW) and three different lignocellulosic wastes (LW) (Corn stover (CS), Prairie cordgrass (PCG), and Unbleached paper (UBP)) for thermophilic anaerobic digestion to overcome the limitations of digesting food waste alone (volatile fatty acids accumulation and low C:N ratio). Using an enriched thermophilic methanogenic consortium, all the food and lignocellulosic waste mixtures showed positive synergistic effects of codigestion. After 30 days of incubation at 60 °C (100 rpm), the highest methane yield of 305.45 L·kg−1 volatile solids (VS) was achieved with a combination of FW-PCG-CS followed by 279.31 L·kg−1 VS with a mixture of FW-PCG. The corresponding volatile solids reduction for these two co-digestion mixtures was 68% and 58%, respectively. This study demonstrated a reduced hydraulic retention time for methane production using FW and LW.
APA, Harvard, Vancouver, ISO, and other styles
4

Tatsuzawa, T., L. Hao, S. Ayame, T. Shimomura, N. Kataoka, and A. Miya. "Population dynamics of anaerobic microbial consortia in thermophilic methanogenic sludge treating paper-containing solid waste." Water Science and Technology 54, no. 9 (2006): 113–19. http://dx.doi.org/10.2166/wst.2006.870.

Full text
Abstract:
To maintain a stable thermophilic (55 °C) anaerobic digestion treating toilet paper-containing garbage, it is necessary to operate the digester at long hydraulic retention time (HRT) and low organic loading rate (OLR). Critical conditions of the digestion were investigated by operating the digester at HRT 23 days and OLR 3.4 gCODCr/L/d (R1) or HRT 14 days and OLR 5.6 gCODCr/L/d (R2) separately. Characteristics of methanogenesis of the two digesters were examined by measuring gas generation volume and volatile fatty acids (VFA) concentration, and the populations of four anaerobic acidogens and three methanogens were analyzed using quantitative PCR method. In digester R1, methanogenic activity was unstable but it could be recovered by stopping feeding as though VFA accumulation occurred. The population of acidogens and two methanogens were maintained at 1011–1013 copies/L, however, the population of Methanoculleus could not be recovered after methanogenesis recovering. In digester R2, the period of methanogenesis was significantly shorter than that in digester R1. Both the acidogens and the methanogens could not be maintained at a stable concentration. It is suggested that the critical HRT to sustain the population of acidogens in this process should be longer than 14 days and for all kinds of methanogens, HRT should be longer than 23 days.
APA, Harvard, Vancouver, ISO, and other styles
5

Nikitina, Anna A., Artem A. Ermoshin, Elena A. Zhuravleva, et al. "Application of Polyacrylamide Flocculant for Stabilization of Anaerobic Digestion under Conditions of Excessive Accumulation of Volatile Fatty Acids." Applied Sciences 11, no. 1 (2020): 100. http://dx.doi.org/10.3390/app11010100.

Full text
Abstract:
Excessive accumulation of volatile fatty acids (VFA) is one of the major factors destabilizing methanogenic digestion of organic wastes in anaerobic bioreactors. Existing methods of stabilization of this process are mostly expensive and labor-intensive, often requiring removal of a considerable portion of acidified biomass from the bioreactor. We propose a method for methanogenesis restoration in such soured reactors by the addition of a cationic polyacrylamide flocculant (PAM) at 20 mg/g total solids. After flocculant addition, mixing should be minimized to prolong the existence of the floccules formed in the presence of the flocculant. While partial microbial degradation of the polyacrylamide flocculant was observed during the thermophilic anaerobic process, complete PAM mineralization did not occur. Significant inhibition of anaerobic processes, primarily in the activity of syntrophic propionate-oxidizing bacteria, was observed at PAM concentrations above 40 mg/g total solids.
APA, Harvard, Vancouver, ISO, and other styles
6

Gómez-Quiroga, Xiomara, Kaoutar Aboudi, Carlos José Álvarez-Gallego, and Luis Isidoro Romero-García. "Enhancement of Methane Production in Thermophilic Anaerobic Co-Digestion of Exhausted Sugar Beet Pulp and Pig Manure." Applied Sciences 9, no. 9 (2019): 1791. http://dx.doi.org/10.3390/app9091791.

Full text
Abstract:
In this paper, the viability of thermophilic anaerobic co-digestion of exhausted sugar beet pulp (ESBP) and pig manure (PM) was evaluated. The effect of the proportion of ESBP on biogas production was investigated by using a series of lab-scale batch assays, in duplicates. The following five ESBP:PM mixture ratios were studied: 0:100, 10:90, 25:75, 50:50, and 100:0. The highest cumulative methane production (212.4 mL CH4/g VSadded) was reached for the mixture 25:75. The experimental results showed that the increase in the proportion of ESBP in the mixture led to the distortion of the process, due to acidification by the volatile fatty acids generated. Acetic acid was the predominant acid in all the cases, representing more than 78% of the total acidity. Moreover, the results obtained by operating at thermophilic temperatures have been compared with those obtained in a previous study conducted at mesophilic temperatures. The results have shown that in the individual digestion of ESBP, the activity of acetoclastic methanogens was affected in both temperatures, but especially in thermophilic conditions. Thus, the methane produced in the individual thermophilic digestion of ESBP came almost entirely from the activity of hydrogen-utilizing methanogenic archaea.
APA, Harvard, Vancouver, ISO, and other styles
7

Wang, L. Y., R. Y. Duan, J. F. Liu, S. Z. Yang, J. D. Gu, and B. Z. Mu. "Molecular analysis of the microbial community structures in water-flooding petroleum reservoirs with different temperatures." Biogeosciences 9, no. 11 (2012): 4645–59. http://dx.doi.org/10.5194/bg-9-4645-2012.

Full text
Abstract:
Abstract. Analyses of microbial communities from six water-flooding petroleum reservoirs at temperatures from 21 to 63 °C by 16S rRNA gene clone libraries indicates the presence of physiologically diverse and temperature-dependent microorganisms in these subterrestrial ecosystems. In samples originating from high-temperature petroleum reservoirs, most of the archaeal sequences belong to thermophiles affiliated with members of the genera Thermococcus, Methanothermobacter and the order Thermoplasmatales, whereas bacterial sequences predominantly belong to the phyla Firmicutes, Thermotogae and Thermodesulfobacteria. In contrast to high-temperature petroleum reservoirs, microorganisms belonging to the Proteobacteria, Methanobacteriales and Methanomicrobiales were the most encountered in samples collected from low-temperature petroleum reservoirs. Canonical correspondence analysis (CCA) revealed that temperature, mineralization, ionic type as well as volatile fatty acids showed correlation with the microbial community structures, in particular members of the Firmicutes and the genus Methanothermobacter showed positive correlation with temperature and the concentration of acetate. Overall, these data indicate the large occurrence of hydrogenotrophic methanogens in petroleum reservoirs and imply that acetate metabolism via syntrophic oxidation may represent the main methanogenic pathway in high-temperature petroleum reservoirs.
APA, Harvard, Vancouver, ISO, and other styles
8

Nozhevnikova, Alla N., C. Holliger, A. Ammann, and A. J. B. Zehnder. "Methanogenesis in sediments from deep lakes at different temperatures (2–70°C)." Water Science and Technology 36, no. 6-7 (1997): 57–64. http://dx.doi.org/10.2166/wst.1997.0575.

Full text
Abstract:
Methanogenic degradation of organic matter occurs in a wide temperature range from psychrophilic to extreme thermophilic conditions. Mesophilic and thermophilic methanogenesis is relatively well investigated, but little is known about low temperature methanogenesis and psychrophilic methanogenic communities. The aim of the present work was to study methanogenesis in a wide range of temperatures with samples from sediments of deep lakes. These sediments may be considered deposits of different types of microorganisms, which are constantly exposed to low temperatures. The main question was how psychrophilic methanogenic microbial communities compare to mesophilic and thermophilic ones. Methanogenesis in a temperature range of 2–70°C was investigated using sediment samples from Baldegger lake (65 m) and Soppen lake (25 m), Switzerland. Methane production from organic matter of sediments occurred at all temperatures tested. An exponential dependence of methane production rate was found between 2 and 30°C. Methanogenesis occurred even at 70°C. At the same time stable methane production from organic matter of sediments was observed at temperatures below 10°C. Methanogenic microbial communities were enriched at different temperatures. The communities enriched at 4–8°C had the highest activity at low temperatures indicating that a specific psychrophilic community exists. Addition of substrates such as cellulose, volatile fatty acids (butyrate, propionate, acetate), methanol and H2/CO2 stimulated methane production at all temperatures. H2/CO2 as well as methanol were directly converted to methane under thermophilic conditions. At low temperatures these substrates were converted to methane by a two-step process. First acetate was formed, followed by methane production from acetate. When acetate concentrations were high, acetoclastic methanogenesis was inhibited at low temperatures. This reaction appears to be one of the “bottle neck” in psychrophilic methanogenesis.
APA, Harvard, Vancouver, ISO, and other styles
9

Lepistö, Raghida, and Jukka Rintala. "The effect of extreme temperatures (70–80°C) on the effluent quality and sludge characteristics of UASB reactors." Water Science and Technology 36, no. 6-7 (1997): 325–32. http://dx.doi.org/10.2166/wst.1997.0607.

Full text
Abstract:
The study focused on the effluent quality and sludge characteristics during the start-up and operation of extreme thermophilic (70 to 80°C) upflow anaerobic sludge bed (UASB) reactors, inoculated with mesophilic and thermophilic granular sludge and fed with acetate, volatile fatty acids (VFA), and thermomechanical pulping (TMP) whitewater. Low effluent quality and long start-up periods were observed during the start-up of the 70 to 76°C, VFA-fed UASB reactors inoculated with mesophilic granulae, while better effluent quality and considerably shorter start-up periods were observed when thermophilic (55/70°C) inocula were used. With VFA feed, a significant amount of acetate was removed at 70°C and even at 80°C, while propionate removal was negligible. With TMP whitewater feed, low VFA effluent concentration was obtained at 70°C. The volatile solids (VS) and the VS/total solids (TS) content of the sludge decreased significantly during the first 2–3 months of operation when mesophilic inocula were used. The initial specific methanogenic activity (ISMA) of the extreme thermophilic sludge decreased with increasing temperature and was slightly higher on glucose than on acetate. At 70 to 80°C, various rod-like bacteria were dispersed through the granulae in either individual or in low density micro colonies surrounded with a varying degree of precipitates.
APA, Harvard, Vancouver, ISO, and other styles
10

Syutsubo, Kazuaki, Hideki Harada, and Akiyoshi Ohashi. "Granulation and sludge retainment during start-up of a thermophilic UASB reactor." Water Science and Technology 38, no. 8-9 (1998): 349–57. http://dx.doi.org/10.2166/wst.1998.0825.

Full text
Abstract:
A laboratory-scale UASB reactor was operated at 55°C over 600 days in order to investigate the granulation mechanism under thermophilic conditions. The reactor was seeded with a thermophilic digested sewage sludge, and fed with a synthetic wastewater composed of sucrose and volatile fatty acids. As a result of establishment of the whole granulated sludge bed, the reactor allowed ultimately a volumetric COD loading of 45 kgCOD m−3 d−1 with 90% COD removal. The maximum sludge loading achieved was 3.7 gCOD·gVSS−1 d−1, that is two to three times as large as that of mesophilically grown sludge. The behavior of SRT (sludge retention time) was closely correlated with the biogas evolution flux: excessive biogas evolution at the highest COD loading (45 kgCOD m−3 d−1) enhanced the sludge washout, and thus led to shortening of SRT into less than 7 days. Methanogenic activities of the retained sludge increased finally up to 110 times for acetate, 25 times for propionate, and 3.6 times for hydrogen as large as those of the seeded sludge.
APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic "Volatile fatty acids; Thermophil; methanogenic"

1

McDougall, Forbes Russell. "Optimization and evaluation of the acidification stage of a two-phase anaerobic digester treating coffee wastewater." Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318254.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Book chapters on the topic "Volatile fatty acids; Thermophil; methanogenic"

1

Pandey, Deepak, Morteza Mansouryar, Margarita Novoa-Garrido, et al. "Nutritional and anti-methanogenic potentials of macroalgae for ruminants." In Seaweed and microalgae as alternative sources of protein. Burleigh Dodds Science Publishing, 2021. http://dx.doi.org/10.19103/as.2021.0091.14.

Full text
Abstract:
The livestock production sector is facing challenges to find alternative feed resources and nutritional strategies to mitigate enteric methane (CH4) emissions from ruminants. Recently, marine macroalgae have emerged as potential anti-methanogenic feed ingredients due to their ability to suppress enteric CH4 production in ruminants. The anti-methanogenic properties of macroalgae have been ascribed to the contents of secondary metabolites, such as halogenated compounds e.g., bromoform in red species, and polyphenols or isoprenoids in brown species. These compounds may suppress methanogenesis by inhibiting the growth and activity of methanogens or by altering rumen fermentation pathways and the patterns of volatile fatty acids production. On the other hand, the anti-methanogenic macroalgae, particularly when added to diets in large amounts, are known to reduce animal performance, due to the presence of special and poorly degradable carbohydrates. Thus, finding a proper balance between the abilities to reduce CH4 emissions and sustain animal performance is important.
APA, Harvard, Vancouver, ISO, and other styles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography