Microbial diversity in a full-scale anaerobic reactor treating high concentration organic cassava wastewater

Abstract

Microbial characteristics in the up-flow anaerobic sludge blanket reactor (UASB) of a full-scale high concentration cassava alcohol wastewater plant capable of anaerobic hydrocarbon removal were analyzed using cultivation-independent molecular methods. Forty-five bacterial operational taxonomic units (OTUs) and 24 archaeal OTUs were identified by building 16S rRNA gene of bacterial and archaeal clone libraries. Most bacterial OTUs were identified as phyla of Firmicutes (53.3%), Chloroflexi (20.0%), Proteobacteria (11.1%), Bacteroidetes (6.7%) and a candidate division (2.2%). Methanosaeta (57.5%) were the most abundant archaeal group, followed by Methanobacterium (10.6%), Methanomethylovorans (8.5%) and Methanosarcina (6.4%). Most bacterial species take charge of cellulolysis, proteolysis, acidogenesis and homo-acetogenesis; the most methanogens were typical hydrogenotrophic or hydrogenotrophic/aceticlastic. This study revealed a succession of both bacterial and archaeal populations during the trial, which could be linked to operational adaptation of high concentration organic cassava wastewater.

Keywords: Full-scale, anaerobic reactor, 16S rRNA gene clone library, microbial diversity, functional analysis.