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Novel Biocatalysts for Lignocellulose Consolidated Bio-Saccharification

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 Technology (QIBEBT) of the Chinese Academy of Sciences developed novel biocatalysts for consolidated bio-saccharification (CBS), providing a new strategy for cost-efficient lignocellulose conversion. 

Through long-term research on Clostridium thermocellum (C. thermocellum) and its cellulosome system, the researchers developed CBS which uses cellulosome-based biocatalysts for hydrolysis and produces fermentable sugars as the product for flexible coupling with various downstream applications. 

They have constructed two generations of CBS biocatalysts in the previous study 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 would lead to the 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. (Image by LIU Yajun) 

(Text by LIU Yajun)

Contact:

CHENG Jing

Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences

Tel: 86-532-80662647/80662622

E-mail: chengjing@qibebt.ac.cn

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