Integration of strain engineering with bioprocess engineering strategies to enhance biobased production of value-added chemicals

到目前为止，大多数化工产品仍然是以化石燃料为原料通过化学加工制成的，这不仅会消耗化石燃料，而且会产生大量的温室气体(GHGs)。因此，用现代生物基生产取代化学生产可能为温室气体减排和可持续制造提供真正的解决方案，实现“低碳”经济。拟议的研究将针对新型工程细菌大肠杆菌菌株的生物技术开发及其相关的生物处理策略，以实现清洁、有效、经济、可再生和可持续的增值化学品生产。最近，我们成功地在工程大肠杆菌中通过激活天然睡美人变位酶(SBM)途径来异源生产非天然正丙醇和丙酸。与我们的论证相关的一个重要含义是，SBM途径的激活引入了一条C3发酵途径，在大肠杆菌中形成了非天然代谢物中间产物丙酰辅酶A。丙酰辅酶A的存在为利用大肠杆菌作为细胞工厂从无关的碳源中合成一系列非天然高价值生物产品开辟了广阔的道路。在这项拟议的研究中，丙酰辅酶A衍生的两种有价值的生物产品，即3-羟基戊酸酯(3-HV)和戊酸酯，将用于技术演示。首先，我们将应用各种最先进的微生物生物技术，包括合成生物学、基因/基因组工程、蛋白质工程和代谢工程，进一步改造这些产生丙醇的大肠杆菌菌株，用于异源生产3-HV和戊酸酯。此外，我们将利用甘油、木质纤维素酶和挥发性脂肪酸等廉价原料探索这些工程菌株的有效生物转化。最后，我们将表征和优化大规模生产的操作条件和生物处理策略，并评估开发的生物工艺的经济可行性。预计拟议研究在开发有效的基于生物的生产平台方面的成功将促进生物制造的科学和工程进步，提高生物加工的经济可行性，并减轻传统化学加工造成的重大环境影响。经过改造的细菌菌株和开发的生物工艺可以很容易地转移到我们的加拿大工业合作伙伴进行商业化，增强加拿大在生物制造方面的技术领先地位。此外，拟议的研究是高度多学科的，因为其技术方面涵盖了基础生物科学和实际的生化工程应用；因此，将是培训高素质人才(HQP)的理想选择，以迎接下一代工业生物技术的挑战。

To date, most chemical products are still made via chemical processing with fossil fuels as raw materials, not only depleting fossil fuels but also generating significant amounts of greenhouse gases (GHGs). Hence, replacing chemical production with modern biobased production potentially offers a true solution to both GHG mitigation and sustainable manufacturing, realizing "low carbon" economy. The proposed research will target biotechnological development of novel engineered bacterial Escherichia coli strains and their associated bioprocessing strategies for clean, effective, economical, renewable, and sustainable production of value-added chemicals. Recently, we successfully demonstrated heterologous production of non-native 1-propanol and propionate in engineered E. coli through activation of a natural sleeping beauty mutase (Sbm) pathway. An important implication associated with our demonstration is that activation of the Sbm pathway introduces a C3-fermentative pathway with the formation of a non-native metabolite intermediate propionyl-CoA in E. coli. The presence of propionyl-CoA opens a wide avenue for novel bacterial synthesis of a selection of non-native high-value bioproducts from unrelated carbon sources using E. coli as a cell factory. In this proposed research, two valuable bioproducts derived from propionyl-CoA, i.e. 3-hydroxyvalerate (3-HV) and valerate, will be used for technological demonstration. First, we will apply various state-of-the-art microbial biotechnologies, including synthetic biology, genetic/genomic engineering, protein engineering, and metabolic engineering to further engineer these propanologenic (propanol-producing) E. coli strains for heterologous production of 3-HV and valerate. Additionally, we will explore these engineered bacterial strains for effective biotransformation using cheap feedstocks, including glycerol, lignocelluloses, and volatile fatty acids. Finally, we will characterize and optimize operating conditions and bioprocessing strategies for large-scale production and evaluate the economic feasibility of developed bioprocesses. It is anticipated that the success of the proposed research in developing effective biobased production platforms will mediate scientific and engineering advances in biomanufacturing, enhance economic feasibility of bioprocessing, and alleviate major environmental impacts caused by traditional chemical processing. The engineered bacterial strains and developed bioprocesses can be readily transferred to our Canadian industrial partners for commercialization, boosting Canada's technological leadership in biomanufacturing. In addition, the proposed research is highly multidisciplinary as its technological aspects cover both fundamental biological sciences and practical biochemical engineering applications; and therefore will be ideal for training of highly qualified personnel (HQP) meeting the challenges of the next generation of industrial biotechnology.**