Institute of Systems Biotechnology, Saarland University, Campus A1 5, 66123, Saarbrücken, Germany.
Centre for Biotechnology, Bielefeld University, Bielefeld, Germany.
Microb Cell Fact. 2023 Oct 28;22(1):222. doi: 10.1186/s12934-023-02215-x.
Oxytetracycline which is derived from Streptomyces rimosus, inhibits a wide range of bacteria and is industrially important. The underlying biosynthetic processes are complex and hinder rational engineering, so industrial manufacturing currently relies on classical mutants for production. While the biochemistry underlying oxytetracycline synthesis is known to involve polyketide synthase, hyperproducing strains of S. rimosus have not been extensively studied, limiting our knowledge on fundamental mechanisms that drive production.
In this study, a multiomics analysis of S. rimosus is performed and wild-type and hyperproducing strains are compared. Insights into the metabolic and regulatory networks driving oxytetracycline formation were obtained. The overproducer exhibited increased acetyl-CoA and malonyl CoA supply, upregulated oxytetracycline biosynthesis, reduced competing byproduct formation, and streamlined morphology. These features were used to synthesize bhimamycin, an antibiotic, and a novel microbial chassis strain was created. A cluster deletion derivative showed enhanced bhimamycin production.
This study suggests that the precursor supply should be globally increased to further increase the expression of the oxytetracycline cluster while maintaining the natural cluster sequence. The mutagenized hyperproducer S. rimosus HP126 exhibited numerous mutations, including large genomic rearrangements, due to natural genetic instability, and single nucleotide changes. More complex mutations were found than those typically observed in mutagenized bacteria, impacting gene expression, and complicating rational engineering. Overall, the approach revealed key traits influencing oxytetracycline production in S. rimosus, suggesting that similar studies for other antibiotics could uncover general mechanisms to improve production.
土霉素来源于链霉菌属，能抑制多种细菌，具有重要的工业价值。其潜在的生物合成过程复杂，阻碍了理性工程，因此工业生产目前依赖于经典的突变体进行生产。虽然土霉素合成的生物化学基础已知涉及聚酮合酶，但对产率较高的链霉菌属菌株的研究并不广泛，限制了我们对驱动生产的基本机制的了解。
本研究对链霉菌属进行了多组学分析，并比较了野生型和高产菌株。获得了驱动土霉素形成的代谢和调控网络的见解。高产菌株表现出增加的乙酰辅酶 A 和丙二酰辅酶 A 供应，上调的土霉素生物合成，减少竞争副产物的形成，以及简化的形态。这些特征被用于合成比马霉素，一种抗生素，并创建了一个新的微生物底盘菌株。簇缺失衍生物显示出增强的比马霉素产量。
本研究表明，应该全局增加前体供应，以在保持天然簇序列的同时进一步提高土霉素簇的表达。由于自然遗传不稳定性，诱变高产的链霉菌属 HP126 表现出许多突变，包括大型基因组重排和单核苷酸变化。与诱变细菌中通常观察到的突变相比，发现了更复杂的突变，影响基因表达，使理性工程变得复杂。总的来说，该方法揭示了影响土霉素在链霉菌属属生产的关键特征，表明对其他抗生素进行类似的研究可能会发现提高生产的一般机制。
