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

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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.