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Microbial dynamics in anaerobic digestion reactors for treating organic urban residues during the start‐up process
Author(s) -
AlcántaraHernández R.J.,
Taş N.,
CarlosPinedo S.,
DuránMoreno A.,
Falcón L.I.
Publication year - 2017
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/lam.12734
Subject(s) - anaerobic digestion , methanosaeta , biogas , mesophile , pulp and paper industry , biology , microbial population biology , biomass (ecology) , biodegradable waste , sewage treatment , bioenergy , food science , microbiology and biotechnology , biofuel , environmental science , bacteria , methane , agronomy , environmental engineering , ecology , genetics , engineering
Anaerobic digestion of organic residues offers economic benefits via biogas production, still methane ( CH 4 ) yield relies on the development of a robust microbial consortia for adequate substrate degradation, among other factors. In this study, we monitor biogas production and changes in the microbial community composition in two semi‐continuous stirred tank reactors during the setting process under mesophilic conditions (35°C) using a 16S rDNA high‐throughput sequencing method. Reactors were initially inoculated with anaerobic granular sludge from a brewery wastewater treatment plant, and gradually fed organic urban residues (4·0 kg VS m −3 day −1 ) . The inocula and biomass samples showed changes related to adaptations of the community to urban organic wastes including a higher relative proportion of Clostridiales, with Ruminococcus spp. and Syntrophomonas spp. as recurrent species. Candidatus Cloacamonas spp. (Spirochaetes) also increased from ~2·2% in the inoculum to >10% in the reactor biomass. The new community consolidated the cellulose degradation and the propionate and amino acids fermentation processes. Acetoclastic methanogens were more abundant in the reactor, where Methanosaeta spp. was found as a key player. This study demonstrates a successful use of brewery treatment plant granular sludge to obtain a robust consortium for methane production from urban organic solid waste in Mexico. Significance and Impact of the Study This study describes the selection of relevant bacteria and archaea in anaerobic digesters inoculated with anaerobic granular sludge from a brewery wastewater treatment plant. Generally, these sludge granules are used to inoculate reactors digesting organic urban wastes. Though, it is still not clearly understood how micro‐organisms respond to substrate variations during the reactor start‐up process. After feeding two reactors with organic urban residues, it was found that a broader potential for cellulose degradation was developed including Bacteroidetes, Firmicutes and Spirochaetes. These results clarify the bacterial processes behind new reactors establishment for treating organic wastes in urban areas.