Bioaugmentation of the thermophilic anaerobic biodegradation of lignocellulose-rich substrates

摘要

Two stable, thermophilic mixed cellulolytic consortia were enriched from an industrial scale biogas fermenter. The two consortia, marked as AD1 and AD2, were used for bioaugmentation in laboratory scale batch reactors. They enhanced the methane yieldby 22-24%. Next generation DNA metagenome sequencing revealed the predominant strains were Thermoanaerobacterium thermosaccharolyticum, Caldanaerobacter subterraneus, Thermoanaerobacterpseudethanolicus and Clostridium cellulolyticum. The effect of thesestrains, cultivated in pure cultures, was investigated with the aim of reconstructing the defined cellulolytic consortium. The addition of the four bacterial strains and their mixture to the biogas fermenters enhanced the methane yield by 10-11% but it was not as efficient as the original communities indicating the significant contribution by members of the enriched communities present in low abundance.