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Nanoparticles in Methane Production from Anaerobic Digesters
Published in Madan L. Verma, Nanobiotechnology for Sustainable Bioenergy and Biofuel Production, 2020
Efraín Reyes Cruz, Lilia Ernestina Montañez Hernández, Inty Omar Hernández De Lira, Nagamani Balagurusamy
Among the microbial populations present in paddy soil enriched with Fe3O4 NPs, Desulfovibrio was the dominant species in the family. Desulfovibrionaceae, this sulfate reducing bacteria (SRB), is capable to produce CO2 from the oxidation of acetate (Madigan et al. 2015) which is one of the main components in the medium. Synergistaceae, Dethiosulfovibrionaceae and Anaerolinaceae families were present too. The genera Cloacibacillus and Aminobacterium belong respectively to the first two families and it was assumed that the members are focused on amino acid degradation released from dead cells. Other observed bacterial families in paddy soil were Acholeplasmataceae, Comamonadaceae and Pseudomonadaceae. These groups consisted of the genera Acholeplasma, Diaphorobacter and Pseudomonas, respectively, but the role of the first two was unknown. In the case of Pseudomonas, they are capable to reduce Fe(III) with H2 as an electron donor. Clostridiaceae, in which Clostridium was the dominant genus, are fermentative bacteria capable of oxidizing acetate in a syntrophic relation with hydrogen scavenger microorganisms such as members of Methanobacteriaceae, an archaeal family composed of hydrogenotrophic methanogens that are also found in the medium. Moreover, the presence of Rhodocyclaceae was predominant, within this family the genera Thauera and Dechloromonas were abundant and both can reduce Fe(III) using acetate. Furthermore, Methanosaeta was also detected (Yang et al. 2015).
Production of Biomass-Based Butanol
Published in Jitendra Kumar Saini, Surender Singh, Lata Nain, Sustainable Microbial Technologies for Valorization of Agro-Industrial Wastes, 2023
The most common natural fermentative microorganism in butanol fermentation is Clostridium spp. The genus of this bacteria is Firmicutes, and family is Clostridiaceae. Clostridium spp. is a rod-shaped, gram-positive, obligate anaerobic bacteria. Louis Pasteur in 1861 reported for the first time about butanol production by Vidrion butyrique, which was actually a mixed culture (Dürre 2008). Later, Weizmann isolated Clostridium acetobutylicum (Jones and Woods 1986).
Occupational exposure to anaerobic bacteria in a waste sorting plant
Published in Journal of the Air & Waste Management Association, 2021
Marcin Cyprowski, Anna Ławniczek-Wałczyk, Agata Stobnicka-Kupiec, Rafał L. Górny
The knowledge about anaerobic bacteria that have temporarily or permanently restricted access to oxygen in the atmosphere is still scarse. In municipal environment, their presence is associated with the decay of waste, usually accompanied by biogas production (Liaquat et al. 2017). This is usually evident during composting processes, when, depending on the prevailing temperature and humidity, specific communities of microorganisms are formed. They are capable decomposing large molecular organic compounds (primarily cellulose and pectins), to produce hydrogen and methane. The most often mentioned in this context are anaerobic bacteria of Thermoanaerobacteriaceae and Clostridiaceae families (Nissilä et al. 2011), as well as of Methanosarcina, Methanosaeta, Methanobrevibacter, and Methanobacterium genera (Ike et al. 2010). Among these groups a special position has Clostridium genus, of which about 35 species can cause clinically important adverse effects, mainly due to the release of their toxins (Samul et al. 2013). In waste samples, both the common environmental strains (e.g., Clostridium butyricum) as well as species pathogenic for humans (such as Clostridium perfringens) can be found (Neuhaus, Shehata, and Krüger 2015). In total of 203 waste samples these researchers identified 11 species of the Clostridium genus, with C. perfringens being the most frequently isolated (nearly 60% of samples). Due to the production of endospores, which gives the ability to maintain its long-term viability, this species, along with Enterococcus genus and intestinal coliform rods, is considered as an indicator of fecal pollution of the environment (Lisle et al. 2004; Pillai et al. 1996; Unc, Niemi, and Goss 2015).
Influence of initial pH on the production of volatile fatty acids and hydrogen during dark fermentation of kitchen waste
Published in Environmental Technology, 2021
Radosław Slezak, Justyna Grzelak, Liliana Krzystek, Stanisław Ledakowicz
Based on the conducted research, it was observed that the ammonia contained in the inoculum allowed buffering pH during the dark fermentation of KW. Increasing the initial pH resulted in a slight growth in operational pH, which was associated with a greater decomposition of organic matter, including proteins from which ammonia was formed. The conducted research allowed determination of the initial pH, at which the highest yield of VFAs and H2 production was obtained. The largest production of VFAs (about 14 g/L) was achieved at the initial pH of 8, and the content of acetic and butyric acids was 52 and 42%, respectively. Due to the high VFAs/TOC ratio (0.86) at the initial pH of 8, the production of ethanol and lactic acid was at a very low level. In contrast, the maximum production of H2 (82.6 mL/gVS) was achieved at a slightly lower initial pH of 7. However, the yield of H2 production at initial pH of 8 was 10% lower than maximum yield. For the initial pH of 8, the lag phase duration during H2 production increased to a value about 5 h compared to bioreactor in which initial pH was 7. During dark fermentation, CO2 was also formed, the production yield of which was close to that of VFAs. At the initial pH of 6, the highest growth of Lactobacillaceae bacteria was observed and at the initial pH of 8 Clostridiaceae one. Despite the presence of Lactobacillaceae bacteria at the initial pH of 8 no lactic acid production was observed. The increased production of VFAs and H2 for the initial pH of 8 resulted in a greater diversity of the microbial community. Dominant micro-organisms at the initial pH of 8 were Bacteroidetes, Firmicutes, Spirochaetes and WWE1 at the phylum level.
Microflora communities which can convert digested sludge to biogas
Published in Environmental Technology, 2022
Ayaka Kon, Shunsuke Omata, Yuhei Hayakawa, Nobuhiro Aburai, Katsuhiko Fujii
DGGE analysis revealed that each of the DABYS and DABYE includes a wide variety of eubacteria. All the DABYS and DABYE differ in origin, but were found to comprise mainly bacteria from the Enterobacteriaceae and Clostridiaceae families. As for the Enterobacteriaceae family, Citrobacter freundii produces cellulase, chitinase, and protease [35] and Cronobacter sakazakii produces chitinase and protease [36,37]. Therefore, the amplicons-E1, E2, E6, and E7 represent bacteria that may contribute to DS hydrolysis via their carbohydrate and protein-hydrolyzing activity. Since Enterobacter asburiae is known as a proteolytic species [38], the amplicons-E3, E4, E5, E8, and E9 represent bacteria that might metabolize DS via their protease activity. The strain corresponding to amplicon-H1, which revealed a sequence that was closely related to Pseudobacteroides cellulosolvens and Ruminiclostridium cellobioparum, was specifically found in all the DABYE microflora. Since both species are known to possess cellulase [39,40], the bacterial species represented by amplicon-H1 may contribute to degradation of cellulose in DS. Some of the microfloral communities contained Acinetobacter (amplicon M1) which contains cellulolytic, chitinolytic, and proteolytic species [41–43]. Hence the strain represented by the amplicon M1 may also hydrolyze DS. By contrast, Clostridium amylolyticum and C. punense, members of the Clostridiaceae family, are reported to produce hydrogen, but do not produce cellulase, chitinase, or protease [44,45], suggesting that amplicons C1, C2, and C3 represent hydrogen-producing bacteria. There are no reports of the hydrolase enzymes or hydrogen-producing activity for the Fonticella tunisiensis and Lutispora thermophila, species of thermophilic bacteria found in hot springs [46] and in a methanogenic bioreactor [47], implying that the amplicons C4, C5, C6, and C7 represent bacteria that play roles in biogas production that are currently unknown.