Exploitation of Bacillus subtilis as a robust workhorse for production of heterologous proteins and beyond

Abstract

Bacillus subtilis, belonging to the type species of Bacillus, is a type of soil-derived, low %G+C, endospore-forming Gram-positive bacterium. After the discovery of B. subtilis 168 that displayed natural competence, this bacterium has been intensively considered to be an ideal model organism and a robust host to study several basic mechanisms, such as metabolism, gene regulation, bacterial differentiation, and application for industrial purposes, such as heterologous protein expression and the overproduction of an array of bioactive molecules. Since the first report of heterologous overproduction of recombinant proteins in this strain, the bulk production of a multitude of valuable enzymes, especially industrial enzymes, has been performed on a relatively large scale. Since B. subtilis can non-specifically secrete recombinant proteins using various signal peptides, it has tremendous advantages over Gram-negative bacterial hosts. Along with the report of the complete genome sequence of B. subtilis, a number of genetic tools, including diverse types of plasmids, bacterial promoters, regulatory elements, and signal peptides, have been developed and characterized. These novel genetic elements tremendously accelerated genetic engineering in B. subtilis recombinant systems. In addition, with the development of several complex gene expression systems, B. subtilis has performed a number of more complex functions. This ability enables it to be a substantial chassis in synthetic biology rather than just a workhorse for the overproduction of recombinant proteins. In this review, we review the progress in the development of B. subtilis as a universal platform to overproduce heterologous diverse high-value enzymes. This progress has occurred from the development of biological parts, including the characterization and utilization of native promoters, the fabrication of synthetic promoters and regulatory elements, and the assembly and optimization of genetic systems. Some important industrial enzymes that have been produced in large quantities in this host are also summarized in this review. Furthermore, the ability of B. subtilis to serve as a cellular tool was also briefly recapitulated and reviewed.

Expression of d-psicose-3-epimerase from Clostridium bolteae and Dorea sp. and whole-cell production of d-psicose in Bacillus subtilis

“…3). Promoters are important cis-regulatory elements for regulating gene expression and would impact on protein production (Cui et al 2018). However, previous reports showed that enhancing the strength of the promoter increased enzyme production at different levels, from 7.62 to 79.9% of increase under different dual-promoter strategies (Liu et al 2019;Okegawa and Motohashi 2016).…”

EngineeringBacillusfor efficient production of heterologous protein: current progress, challenge and prospect

“…; Cui et al . ). This review aims to detail the latest developments of hosts for protein expression in Bacillus , including secretion pathway optimization, mRNA and protein stability enhancement, cell growth facilitation, genome streamlining and engineering transcriptional regulators (Table and Fig.…”

“…have been produced by bacteria and fungi, including Escherichia coli, Bacillus, Pichia pastoris, Trichoderma reesei, Aspergillus niger, etc. Compared to other expression systems, Bacillus species are regarded as the promising host strains with various merits, including nontoxicity, convenience for gene modification, short fermentation cycle on cheap nutrition, superior capacity of protein secretion and robustness in industrial fermentation (van Dijl and Hecker 2013;Cui et al 2018).…”

“…Along with the development of molecular biotechnology tools, great achievements have been made in the area of protein expression in Bacillus (Kang et al 2014;Cui et al 2018). This review aims to detail the latest developments of hosts for protein expression in Bacillus, including secretion pathway optimization, mRNA and protein stability enhancement, cell growth facilitation, genome streamlining and engineering transcriptional regulators (Table 1 and Fig.…”

Glucose‐containing polymer rings enable fed‐batch operation in microtiter plates with parallel online measurement of scattered light, fluorescence, dissolved oxygen tension, and pH

“…The most relevant negative metabolic phenomenon occurring in batch mode is carbon catabolite repression. As organisms quickly have to react to changing nutritional conditions, promoters of genes related to catabolism are considered to be strong and are thus frequently used for recombinant protein production (Cui et al, ; Hubmann, Thevelein, & Nevoigt, ; Kluge, Terfehr, & Kück, ; Stöckmann et al, ). However, the induction or repression of these promoters is directly coupled with the availability of the preferred carbon source, which most often is glucose.…”