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Microbial diversity and dynamics in multi‐ and single‐compartment anaerobic bioreactors processing sulfate‐rich waste streams
Author(s) -
Briones Aurelio M.,
Daugherty Becky J.,
Angenent Largus T.,
Rausch Kent D.,
Tumbleson Mike E.,
Raskin Lutgarde
Publication year - 2007
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2006.01119.x
Subject(s) - bioreactor , sulfate , microbial population biology , sulfate reducing bacteria , population , biology , methanogenesis , anaerobic exercise , microbiology and biotechnology , chemical oxygen demand , wastewater , bacteria , terminal restriction fragment length polymorphism , chemistry , food science , biochemistry , environmental engineering , environmental science , botany , physiology , polymerase chain reaction , genetics , demography , organic chemistry , sociology , restriction fragment length polymorphism , gene
Summary We investigated bacterial and archaeal community structures and population dynamics in two anaerobic bioreactors processing a carbohydrate‐ and sulfate‐rich synthetic wastewater. A five‐compartment anaerobic migrating blanket reactor (AMBR) was designed to promote biomass and substrate staging, which partially separates the processes of methanogenesis and sulfidogenesis in the middle and outer compartment(s) respectively. The second reactor was a conventional, single‐compartment upflow anaerobic sludge blanket (UASB) reactor. Both reactors, which were seeded with the same inoculum, performed well when the influent chemical oxygen demand (COD)/SO 4 2– mass ratio was 24.4. The AMBR performed worse than the UASB reactor when the influent COD/SO 4 2– mass ratio was decreased to 5.0 by raising the sulfate load. Terminal restriction fragment length polymorphism analyses of bacterial 16S rRNA genes showed that the increase in sulfate load had a greater impact on bacterial diversity and community structure for the five AMBR compartments than for the UASB reactor. Moreover, bacterial community profiles across AMBR compartments became more similar through time, indicating a converging, rather than a staged community. While similar populations were abundant in both reactors at the beginning of the experiment, fermenting bacteria (clostridia, streptococci), and sulfate‐reducing bacteria became more abundant in the AMBR, after shifting to a higher sulfate load, while a novel Thermotogales ‐like population eventually became predominant in the UASB reactor. A similar shift in the community structure of the hydrogenotrophic methanogens in the AMBR occurred: representatives of the Methanobacteriaceae out‐competed the Methanospirillaceae after increasing the sulfate load in the AMBR, while the archaeal community structure was maintained in the UASB.