Characterization of microbial community structure during continuous anaerobic digestion of straw and cow manure

Abstract

Responses of bacterial and archaeal communities to the addition of straw during anaerobic digestion of manure at different temperatures (37°C, 44°C and 52°C) were investigated using five laboratory-scale semi-continuous stirred tank reactors. The results revealed that including straw as co-substrate decreased the species richness for bacteria, whereas increasing the operating temperature decreased the species richness for both archaea and bacteria, and also the evenness of the bacteria. Taxonomic classifications of the archaeal community showed that Methanobrevibacter dominated in the manure samples, while Methanosarcina dominated in all digesters regardless of substrate. Increase of the operating temperature to 52°C led to increased relative abundance of Methanoculleus and Methanobacterium. Among the bacteria, the phyla Firmicutes and Bacteroidetes dominated within all samples. Compared with manure itself, digestion of manure resulted in a higher abundance of an uncultured class WWE1 and lower abundance of Bacilli. Adding straw to the digesters increased the level of Bacteroidia, while increasing the operating temperature decreased the level of this class and instead increased the relative abundance of an uncultured genus affiliated to order MBA08 (Clostridia). A considerable fraction of bacterial sequences could not be allocated to genus level, indicating that novel phylotypes are resident in these communities.

Microbiota of anaerobic digesters in a full-scale wastewater treatment plant

“…Yuan et al (2015) noted that during fermentation of seed sludge under uncontrolled pH conditions, Proteobacteria predominated consisting of 47.3% Bacteria. Chlorofl exi was a predominant phylum in mesophilic digesters (42.58% and 63.47%) treating diffi cult-to-degrade hydrocarbons with both a high (24%) and low (6%) content of solids (Lu et al 2016), while Firmicutes(53%) predominated in co-digesting of various wastes from restaurants, slaughterhouses, manure and households (Sundberg et al 2013, Sun et al 2015. Firmicutes and Bacteroidetes communities were very stable during the digestion of the substrates in biogas reactors fed with casein, starch, and cream and only starving periods, changes of pH values, or long-time continuous feeding caused species shifts in bacterial community (Kampmann et al 2012).…”

Characterization of the Microbial Communities in Rumen Fluid Inoculated Reactors for the Biogas Digestion of Wheat Straw

“…Acetoclastic methanogenesis accounting for over 70% methane production in anaerobic digesters [43,44], was considered as the major process in the biogas fermentation, and the dominance of the genus Methanosarcina had been found in various anaerobic digesters [45][46][47]. M. barkeri could utilize acetate, methanol, and H 2 -CO 2 for methane production [44,48], which might enhance the competitive ability of Methanosarcina in anaerobic digesters [45]. Besides the importance of acetoclastic methanogenesis, hydrogenotrophic methanogenesis was also important in R10 and R25 with the abundant presence of Methanobacterium in both the reactors.…”

“…The predominance of these two phyla has been characterized in various anaerobic digesters and rumens [45,47,52,53].…”

Sulfate reducing bioreactor dependence on organic substrates for remediation of coal-generated acid mine drainage: Field experiments

“…Bacilli, Clostridia, and Bacteriodia) related to livestock manure used to inoculate the reactors (Pugh, 2013), presumably provided a source of simple OC for SRB (Pruden et al, 2007;Wirth et al, 2012;Sun et al, 2015). In time, the lignin/cellulose ratio of the substrate may have increased as a consequence of bacterial activity because lignin degrades slower than cellulose especially in anaerobic conditions (P erez et al, 2002;Komilis and Ham, 2003;Li et al, 2009).…”