Lignocellulosic biomass is considered as a great substitute for fossil resources for its advantages in carbon emission reduction. Because of the complex composition and recalcitrant structure of lignocellulose, efficient and low-cost lignocellulose saccharification has become one of the main bottlenecks for industrial application.
In a study published in Bioresource Technology, the researchers from Qingdao Institute of Bioenergy and Processes of the Chinese Academy of Sciences developed novel biocatalysts for consolidated bio-saccharification (CBS), a newly proposed strategy for cost-efficient lignocellulose conversion.
Through long-term research on Clostridium thermocellum and its cellulosome system, the researchers developed CBS which uses cellulosome-based biocatalysts for hydrolysis and produces fermentable sugars for flexible coupling with various downstream applications.
They previously constructed two generations of CBS biocatalysts by introducing an exogenous β-Glucosidase (BGL) into C. thermocellum and achieved efficient cellulose hydrolysis and high glucose production. In this study, they achieved high-level expression of BGL in C. thermocellum and constructed the third-generation CBS biocatalyst. They also determined the optimal ratio of extracellular BGL-to-cellulosome activity to be in the range of 5.5 to 21.6.
Besides, the researchers found that, although BGL plays a crucial role in the CBS process, excessive BGL expression or its assembly on the cellulosome led to reduced cellulosome activity.
This study provides essential guidelines for the further improvement of CBS biocatalysts, and deepens the understanding of the cellulosome for cost-effective cellulose saccharification under industrially relevant conditions.
The researchers have constructed a whole-chain process from straw biomass to high-value products based on CBS and a pilot demonstration for straw bioconversion in cooperation with enterprises. This is the first time that Chinese scientists develop a complete technical route for lignocellulose conversion with independent intellectual property rights.
The whole-chain process from straw biomass to high-value products based on CBS technology
Text/ Image by LIU Ya-Jun
Contact:
Prof. LIU Ya-Jun, Ph.D.,
Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences
Tel: 86-532-80662705
E-mail: liuyj@qibebt.ac.cn
Link:
https://www.sciencedirect.com/science/article/pii/S0960852421007811
Qi, K., Chen, C., Yan, F., Feng, Y., Bayer, E.A., Kosugi, A., Cui, Q., Liu, Y.-J. 2021. Coordinated β-glucosidase activity with the cellulosome is effective for enhanced lignocellulose saccharification. Bioresource Technology, 337, 125441.
