Research Progress on the Effect of Autolysis to Bacillus subtilis Fermentation Bioprocess

Abstract

Bacillus subtilis is a gram-positive bacterium, a promising microorganism due to its strong extracellular protein secretion ability, non-toxic, and relatively mature industrial fermentation technology. However, cell autolysis during fermentation restricts the industrial application of B. subtilis. With the fast advancement of molecular biology and genetic engineering technology, various advanced procedures and gene editing tools have been used to successfully construct autolysis-resistant B. subtilis chassis cells to manufacture various biological products. This paper first analyses the causes of autolysis in B. subtilis from a mechanistic perspective and outlines various strategies to address autolysis in B. subtilis. Finally, potential strategies for solving the autolysis problem of B. subtilis are foreseen.

Reducing Cellular Autolysis of Bacillus subtilis to Improve Keratinase Production

“…In this study, we selected the peptidoglycan hydrolase genes lytC , lytD , lytE , lytF , lytG , lytH , cwlC , and cwlS and their associated transcriptional regulator sigD , which act during the growth phase, and the prophage-related peptidoglycan hydrolase genes xlyA , xpf , cwlA , and pcfA as well as the self-feeding-related genes skfA and spbC to monitor for their transcript levels using qRT-PCR. ,− It can be seen from the changes in transcription levels that the expression of these genes is upregulated to varying degrees in the middle and late stages of fermentation (Figure ), which is consistent with the autolysis phenotype of B. subtilis cells.…”

Endogenous cell wall degrading enzyme LytD is important for the biocontrol activity of Bacillus subtilis

“…LytC and LytD are two major autolysins expressed during the vegetative phase of growth in B. subtilis 168. Both enzymes are dispensable for growth but have mutually compensatory roles in cell wall turnover, motility, and cell separation ( Rashid et al., 1995 ; Ren et al., 2022 ). Inconsistent with B. subtilis 168, single deletion of lytD of B. subtilis GLB191 showed significant phenotype, probably due to the different strain.…”

“…The autolysins can be divided into four classes based on their cleave sites: N -acetylglucosaminidases, muramidases, acetyl-muramyl-L-alanine amidases (amidases), and endopeptidases ( Ghuysen et al., 1966 ; Smith et al., 2000 ; Nayyab et al., 2017 ; Angeles and Scheffers, 2021 ). Among them, N -acetylglucosaminidase LytD (or CwlG) and amidase LytC (or CwlB) are two major autolysins of vegetative growth in B. subtilis , and these two autolysins bear 95% of the autolytic activity of the cells ( Smith et al., 2000 ; Horsburgh et al., 2003 ; Ren et al., 2022 ). The autolysins associated with B. subtilis were shown to play a role in several important cellular functions, including differentiation, cell lysis, cell wall growth and turnover, cell separation, competence, and motility ( Smith et al., 2000 ).…”