Engineering microbial co-cultures for complex natural product biosynthesis

许多自然产生的药物分子（例如：抗生素、抗癌药物）是以类似于工业装配线的方式，在不断生长的分子中一点一点地添加不同亚基的长序列反应的结果。当生产发生在单个生物体中时，它给生物体带来了很大的负担，要提供完成生产所需的所有原材料和能量。该项目将研究一种策略，即创造出能够有效生产较大药物分子的特定亚基的生物体，将亚基的生产“分包”给多个生物体，然后将这些亚基结合在一起生产最终产品。如果成功，这将大大提高大分子药物生产的效率，也可以提高识别更有效药物分子的速度。该项目还将通过有针对性的推广和参与研究项目中代表性不足的高中生和大学生，扩大stem培训劳动力的发展。本研究旨在使工程大肠杆菌菌株构成共培养物，以生产具有长而复杂的生物合成途径特征的三种具有代表性的天然产物。每个生物合成途径分为两个独立的模块，每个模块都容纳在一个不同的，专门的大肠杆菌菌株中。这种设计的途径模块化可以减少共培养菌株的代谢负担，提高其生物合成性能，因为每个菌株只负责生物合成的一部分。所涉及的菌株也将单独进行代谢工程，以满足指定途径酶的需要，并最大限度地提高其生物转化能力。此外，单个途径模块的生物合成强度将通过操纵共培养群体的相对比例来平衡生物生产优化。微生物系统将扩大规模，以研究高细胞密度条件下的种群稳定性和生物生产行为。这个项目为复杂分子的设计和工程生产提供了巨大的潜力。关于混合种群中种群比例和代谢活动的动态调节的基本知识将提供对天然微生物混合种群行为的洞察，这将对各种工业和环境重要过程产生影响。

Many naturally-occurring pharmaceutical molecules (for example: antibiotics, anti-cancer drugs) are the result of a long sequence of reactions that add, piece by piece, different subunits to the growing molecule, in a fashion similar to an industrial assembly line. When production occurs in a single organism, it places a large burden on the organism to provide all of the raw materials and energy needed to complete construction. This project will investigate a strategy that creates organisms capable of efficiently producing a particular subunit of the larger drug molecule, "subcontracts" production of subunits to multiple organisms, then brings the subunits together to create the final product. If successful, this could dramatically improve the efficiency of large molecule drug production, and could also increase the speed of identification of more effective drug molecules. This project will also expand the development of a STEM-trained workforce through targeted outreach and engagement of high school and college students from under-represented populations in the research project.This proposed study aims to adapt engineered E. coli strains to constitute co-cultures for production of three representative natural products with characteristically long and complicated biosynthetic pathways. Each biosynthetic pathway is divided into two independent modules, each of which is accommodated in a different, specialized E. coli strain. Such designed pathway modularization allows for reduction of metabolic burden and improvement of biosynthetic performance of the co-culture strains, as each strain is only responsible for one portion of the biosynthesis. The involved strains will also be metabolically engineered individually to meet the needs of the designated pathway enzymes and maximize their bioconversion capabilities. Moreover, the biosynthetic strength of the individual pathway modules will be balanced for bioproduction optimization through manipulation of the relative ratio of the co-culture populations. The microbial systems will be scaled up to investigate population stability and bioproduction behavior under high cell density conditions. This project offers outstanding potential to design and engineer the production of complex molecules. The fundamental knowledge gained regarding the dynamic regulation of population ratios and metabolic activity in mixed populations will provide insight into the behavior of natural microbial mixed populations, which will have implications for a wide variety of industrial and environmentally-important processes.