Title: Microbial dynamics in anaerobic digestion reactors for treating organic urban residues during the start-up process

Abstract

Anaerobic digestion of organic residues offers economic benefits via biogas production, still methane (CH₄) 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.This study describesmore » 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.« less

Authors:

Alcántara-Hernández, R. J.  ^[1];

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Taş, N. ^[2]; Carlos-Pinedo, S. ^[3]; Durán-Moreno, A. ^[3]; Falcón, L. I. ^[4]

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+ Show Author Affiliations

1. Univ. Nacional Autonoma de Mexico (UNAM), Mexico City (Mexico). Inst. de Geology
2. Lawrence Berkeley National Laboratory, Climate and Ecosystem Sciences, Ecology Department, Berkeley CA USA
3. Univ. Nacional Autonoma de Mexico (UNAM), Mexico City (Mexico).Dept. de Ingeniería Química
4. Univ. Nacional Autonoma de Mexico (UNAM), Mexico City (Mexico). Lab. de Ecología Bacteriana, Inst. de Ecología

Publication Date:

Mon Mar 13 00:00:00 EDT 2017

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1580089

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Letters in Applied Microbiology

Additional Journal Information:

Journal Volume: 64; Journal Issue: 6; Journal ID: ISSN 0266-8254

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES