Work

Enhancing cellulase biosynthesis of Bacillus subtilis Z2 by regulating intracellular NADH level

Year: 2025

Type: article

Abstract: Optimizing cellulase biosynthesis in Bacillus subtilis is crucial for enhancing enzymatic yield in lignocellulosic biomass conversion. However, the regulatory mechanisms linking intracellular NAD(H/ + ) levels to cellulase production remain elusive. In this study, we systematically screened 13 genes associated with NAD + biosynthesis and NADH regeneration in B. subtilis Z2. Employing a modular engineering strategy with four distinct modules, we directed metabolic flux to enhance NAD + biosynthesis and NADH regeneration. Key genes ( ycel , nadV , nadM , mdh , and sucB ) were identified, and their co-expression in B. subtilis Z2 resulted in a 13.09-fold increase in intracellular NADH levels and a consequential 2.24- and 2.04-fold enhancement in the filter paper-hydrolyzing (FPase [representing total cellulase]) activity and carboxymethylcellulose (CMCase [representing endoglucanase]) activity, respectively. Experimental validations, including antagonist LaCl 3 treatment and spcF gene deletion, unequivocally established the calcium signaling pathway's role in regulating cellulase gene overexpression in response to elevated intracellular NAD(H/ + ) levels.

Source: iScience

DOI: 10.1016/j.isci.2025.112341

Authors: Shuai Liu, Yi Li, Lin Quan, Hai-Xia Liu, Yang Luo, Yong-Zhong Wang

Institutions: Chongqing University, Chongqing Cancer Hospital

Language: English

Topic: Biofuel production and bioconversion

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: gold

Estimated APC paid: $3,240