Oxytetracycline, a vital antibiotic derived from Streptomyces rimosus, plays a significant industrial role due to its broad-spectrum antibacterial properties. The complexity of its biosynthetic processes has made rational engineering challenging, leading to the reliance on mutagenized strains for production. While the involvement of polyketide synthase in oxytetracycline synthesis is known, the specific mechanisms driving high production in hyperproducing strains like S. rimosus have been underexplored, limiting our understanding of the fundamental processes involved.
A comprehensive multiomics analysis was conducted on S. rimosus strains to compare wild-type and hyperproducing strains, shedding light on the metabolic and regulatory networks influencing oxytetracycline production. The hyperproducer exhibited enhanced supply of acetyl-CoA and malonyl CoA, increased oxytetracycline biosynthesis, reduced formation of competing byproducts, and improved morphology. These traits were leveraged to synthesize bhimamycin, an antibiotic, and to develop a novel microbial chassis strain. A cluster deletion derivative showed enhanced bhimamycin production, suggesting the potential for improving production of other antibiotics through similar strategies.
The study highlighted the importance of increasing precursor supply globally to boost oxytetracycline cluster expression while maintaining the natural cluster sequence. The mutagenized hyperproducer, S. rimosus HP126, displayed a range of mutations, including large genomic rearrangements and single nucleotide changes, impacting gene expression and complicating rational engineering efforts. Understanding the key traits influencing oxytetracycline production in S. rimosus could pave the way for enhancing production of various antibiotics by uncovering general mechanisms to improve efficiency.
The genomic analysis of S. rimosus HP126 revealed significant genetic alterations compared to the wild type, including large rearrangements in the chromosome and plasmid. These changes influenced gene expression patterns, with substantial impacts on global transcription in the hyperproducing strain. The study provided insights into how mutagenesis-related genomic changes drive enhanced oxytetracycline production by altering gene expression at a systems level.
Further investigations into the mutant strain’s proteome revealed an increased abundance of oxytetracycline-synthesizing enzymes, correlating with elevated transcript levels of the biosynthetic pathway. The mutant strain also exhibited higher intracellular levels of CoA thioesters, crucial precursors for oxytetracycline biosynthesis, during the production phase. This streamlined CoA supply likely contributed to the enhanced antibiotic production observed in the hyperproducer.
The study’s findings have broader implications for metabolic engineering and antibiotic production. By refactoring S. rimosus at the genomic level, the production of heterologous polyketides like bhimamycin was successfully achieved, demonstrating the potential for leveraging mutagenized strains to enhance the synthesis of diverse compounds. The systematic approach to strain development and multiomics analysis provides a roadmap for optimizing antibiotic production in industrial settings through targeted genetic modifications and understanding the intricate interplay of genetic, metabolic, and regulatory factors.
Key Takeaways:
– Multiomics analysis of hyperproducing strains of Streptomyces rimosus reveals key metabolic and regulatory mechanisms driving enhanced oxytetracycline production.
– Mutagenized strains exhibit significant genomic rearrangements and mutations impacting gene expression, complicating rational engineering efforts.
– Increased precursor supply, altered gene expression patterns, and streamlined metabolic pathways contribute to heightened antibiotic production in hyperproducing strains.
– Genomic refactoring enables the production of heterologous polyketides, showcasing the potential for leveraging mutagenized strains for diverse compound synthesis in bioproduction.
Tags: strain development, downstream, chromatography, upstream, transcriptomics, centrifugation, metabolic engineering, regulatory, metabolomics, multiomics
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