Transcriptome Analysis of Bacillus licheniformis for Improving Bacitracin Production

Abstract

This study aims to find the targets that may influence the production of bacitracin based on RNA sequencing in Bacillus licheniformis. Transcriptional profiling revealed that (i) the expression of the bacT gene, encoding a type II thioesterase (TEII bac ), was positively correlated with bacitracin production and (ii) the oxygen uptake exhibited significant influence on precursor synthesis. The verified experiments showed that the overexpression of TEII bac with an endogenous promoter increased the bacitracin A titer by 37.50%. Furthermore, the increase of oxygen availability through Vitreoscilla hemoglobin (VHb) expression increased the bacitracin A titer by 126.67% under oxygen-restricted conditions. From the transcriptome perspective, the results of this paper demonstrate that TEII bac and oxygen supply are crucial to bacitracin production. This study also provides insights into the construction of chassis cells for the industrial production of secondary metabolites with a preference for aerobic conditions.

Microbial synthesis of bacitracin: Recent progress, challenges, and prospects

“…The bacitracin synthetase gene cluster comprises bacABC operon and type II thioesterase gene bacT , and the function of latter has not been well analyzed [ 15 ]. Recently, Wu et al demonstrated that bacT expression positively correlated with bacitracin synthesis according to transcriptomic analysis, and overexpression of bacT increased bacitracin A yield by 37.50% [ 16 ]. The bacitracin synthetase gene cluster bacABC is located downstream of bacT , among which, BacA (598 kDa) activates and polymerizes four amino acids (L-Ile, L-Leu, L-Cys, and D-Glu) in the tail of bacitracin, BacB (291 kDa) and BacC (723 kDa) are responsible for the activation and amidation of remaining seven amino acids [ 17 , 18 ] ( Fig.…”

“…Moreover, increasing the dissolved oxygen content augments ATP supply and facilitates antibiotic production [ 69 ]. In particular, Wu et al have increased the availability of oxygen via heterologous expression of Vitreoscilla hemoglobin VHb, thereby increasing bacitracin A titer by 126.67% under the oxygen-restricted conditions [ 16 ].…”

Regulation mechanism and bioactivity characteristic of surfactin homologues with C14 and C15 fatty acid chains

“…Transcriptomic technologies have opened new avenues for guiding the construction of high-production strains by providing a deeper understanding of the genetic background of microorganisms, and allow rapid selection of effective metabolic engineering targets. Bacitracin yield was significantly increased by rational engineering of B. licheniformis on the basis of transcriptome data, demonstrating that TEII bac (encoding type II thioesterase) and oxygen supply are critical for bacitracin production [ 12 ].…”

Recent biotechnological advances and future prospective of Bacillus licheniformis as microbial cell factories

“…Researches on the physiology of B. licheniformis date back to the 1970s, and after half a century of intensive development, the achievements have been impressive. Nowadays, biotechnology has undergone rapid iterations, and multiomics information of B. licheniformis, including genome, transcriptome [2] and proteome [3], has also been accurately presented for better exploitation with the help of advanced bioinformatics techniques. The concept of biomanufacturing has been developed in recent years [4], with this background, the use of B. licheniformis as expression system would be an upgraded roadmap for its application.…”