Abstract

Acetivibrio thermocellus is a key thermophilic, cellulolytic bacterium used in Consolidated bio-saccharification (CBS) for hydrogen production from lignocellulosic biomass. However, the main saccharification product of cellulosic feedstocks, cellobiose, has strong inhibition on A. thermocellus which inhibited cellulase activity and limit overall saccharification and biofuel production efficiency. In this study, a wild-type Acetivibrio thermocellus (strain M3), that could bypass cellobiose inhibition was co-cultured with different hydrogen-producing inocula to test the feasibility of hydrogen production bioaugmentation to eliminate cellobiose inhibition. The results revealed that the addition of A. thermocellus M3 promoted hydrogen production ranging from 42.9 % to 105 %, with the peak hydrogen production obtained from domesticated compost combined with strain M3 (233.02 mL/g). A. thermocellus M3 positively correlated with the hydrogen-producing bacteria. The addition of Acetivibrio thermocellus M3 increased the relative abundance of genes associated with cellulosic feedstocks hydrolysis. Furthermore, the relative abundance of genes associated with stress tolerance and sugar uptake also increased—these genes might help the consolidated bio-saccharification (CBS) hydrogen production system adapt to adverse conditions and thereby alleviate cellobiose inhibition.