Consolidated Bioprocessing of Hemicellulose-Enriched Lignocellulose to Succinic Acid through a Microbial Cocultivation System
Jiasheng Lu, Yang Lv, Yujia Jiang, Min Wu, Bin Xu, Wenming Zhang, Jie Zhou, Weiliang Dong, Fengxue Xin, Min Jiang
Abstract
Consolidated bioprocessing (CBP) has been considered as a cost-effective strategy for the efficient bioconversion of lignocellulosic biomass into valuable chemicals. Microbial consortium can complete the complex CBP process through the cooperation within different microorganisms. In this study, a proof-of-concept CBP microbial consortium was designed, which is composed of a hemicellulase-producing bacterium Thermoanaerobacterium thermosaccharolyticum M5 and a succinic acid production specialist Actinobacillus succinogenes 130Z. The continuous conversion of xylan to xylose by T. thermosaccharolyticum could maintain a high hydrolyzing rate, which would facilitate the following succinic acid production by A. succinogenes 130Z. After the process optimization including inoculation time, pH, and so forth, 32.50 g/L of succinic acid with a yield of 0.39 g/g was obtained from xylan through CBP, representing the highest succinic acid production directly from hemicellulose materials. In addition, 12.51 g/L of succinic acid was directly produced from 80 g/L of untreated corn cob. These results demonstrated that the proof-of-concept application of this CBP-based microbial cocultivation system could be readily adopted for bioconversion of lignocellulosic biomass into other valuable biochemicals.