Engineering Bacillus subtilis for production of 3-hydroxypropanoic acid

Abstract

3-Hydroxypropionic acid (3-HP) is a valuable platform chemical that is used as a precursor for several higher value-added chemical products. There is an increased interest in development of cell factories as a means for the synthesis of 3-HP and various other platform chemicals. For more than a decade, concentrated effort has been invested by the scientific community towards developing bio-based approaches for the production of 3-HP using primarily Escherichia coli and Klebsiella pneumoniae as production hosts. These hosts however might not be optimal for applications in e.g., food industry due primarily to endotoxin production and the pathogenic origin of particularly the K. pneumoniae. We have previously demonstrated that the generally recognized as safe organism Bacillus subtilis can be engineered to produce 3-HP using glycerol, an abundant by-product of the biodiesel industry, as substrate. For commercial exploitation, there is a need to substantially increase the titer. In the present study, we optimized the bioprocess conditions and further engineered the B. subtilis 3-HP production strain. Thereby, using glycerol as substrate, we were able to improve 3-HP production in a 1-L bioreactor to a final titer of 22.9 g/L 3-HP.

Construction of exogenous methanol, formate, and betaine modules for methyl donor supply in methionine biosynthesis

“…Synthetic biology has been widely applied to construct microbial cell factories, which produce various high-valued chemicals, such as 3-hydroxypropanoic acid (Garg et al, 2023), rhamnolipid (Tiso et al, 2020), and odd-chain fatty acids (Park et al, 2020). Using the modularized strategy, synthetic biology can always solve the problems in traditional metabolic engineering and it brings significant possibilities for microbial transformation (Lee et al, 2015;Choi et al, 2019;Cravens et al, 2019).…”

Improved secretory expression and characterization of thermostable xylanase and β-xylosidase from Pseudothermotoga thermarum and their application in synergistic degradation of lignocellulose

“…Compared with Escherichia coli expression system, which cannot secrete the recombinant proteins out of the cell and occasionally accumulate the target proteins as inclusion bodies, B. subtilis is non-pathogenic and can release the target proteins directly into culture medium, greatly facilitating the downstream isolation and purification. Bacillu subtilis ’ large-scale fermentation with high cell density and non-biased codon usage are other attractive features of the expression system ( Zhao et al, 2020 ; Garg et al, 2023 ).…”