Heterologous overproduction of oviedomycin by refactoring biosynthetic gene cluster and metabolic engineering of host strain Streptomyces coelicolor

Abstract

Background Oviedomycin is one among several polyketides known for their potential as anticancer agents. The biosynthetic gene cluster (BGC) for oviedomycin is primarily found in Streptomyces antibioticus. However, because this BGC is usually inactive under normal laboratory conditions, it is necessary to employ systematic metabolic engineering methods, such as heterologous expression, refactoring of BGCs, and optimization of precursor biosynthesis, to allow efficient production of these compounds. Results Oviedomycin BGC was captured from the genome of Streptomyces antibioticus by a newly constructed plasmid, pCBA, and conjugated into the heterologous strain, S. coelicolor M1152. To increase the production of oviedomycin, clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system was utilized in an in vitro setting to refactor the native promoters within the ovm BGC. The target promoters of refactoring were selected based on examination of factors such as transcription levels and metabolite profiling. Furthermore, genome-scale metabolic simulation was applied to find overexpression targets that could enhance the biosynthesis of precursors or cofactors related to oviedomycin production. The combined approach led to a significant increase in oviedomycin production, reaching up to 670 mg/L, which is the highest titer reported to date. This demonstrates the potential of the approach undertaken in this study. Conclusions The metabolic engineering approach used in this study led to the successful production of a valuable polyketide, oviedomycin, via BGC cloning, promoter refactoring, and gene manipulation of host metabolism aided by genome-scale metabolic simulation. This approach can be also useful for the efficient production of other secondary molecules encoded by ‘silent’ BGCs.

Stepwise increase of fidaxomicin in an engineered heterologous host Streptomyces albus through multi-level metabolic engineering

“…), GIs containing a large number of “jumping genes" and optimizing culture conditions, seeking out heterologous hosts with superior performance presents a viable alternative. In S. coelicolor M1152, researchers achieved overproduction of polyketide oviedomycin, through heterologous expression, promoter restructuring, and genome-scale metabolic simulation-assisted strategies [ 34 ]. Similarly, efficient expression of herbicide thaxtomin was achieved through strategies such as heterologous expression, repression protein deficiency, transcription factor overexpression, and fermentation medium optimization [ 35 ].…”