Simultaneous saccharification and butanediol production from unpretreated lignocellulosic biomass using an enzymatic cocktail of a newly constructed bacterial consortium

Abstract

Bioconversion lignocellulosic biomass (LCB) to 2,3-butanediol (2,3-BDO) is a sustainable and energy-intensive practice, but its economic feasibility has been hindered by costly pretreatment and the cumbersome fermentation process. Herein, the hindgut metagenome of Cyrtotrachelus buqueti is assembled and sequenced to construct bacterial consortia for efficient LCB degradation. One of these consortia, named artificial synthetic bacteria community II (ASCII), is effective in degrading unpretreated LCB, achieving degradation rates of 85.33% for cellulose, 77.43% for hemicellulose, and 57.63% for lignin. The secretory protein extracted from ASCII is used for simultaneous saccharification and fermentation (SSF) from unpretreated LCB. Furthermore, fed-batch SSF resulted in 40.62 g/L of 2,3-BDO with a productivity of 0.42 g/L/h reached by Klebsiella sp. CQHG35. This study provides a new approach for the construction of bacterial consortia and their use in SSF for the production of 2,3-BDO from unpretreated LCB, representing a significant breakthrough in this field.