Biosynthesis of Lactate-Containing Polymers in Metabolically Engineered Escherichia coli

Biosynthesis of Lactate Lactate-containing Containing polymer Polymers in Recombinant Metabolically

Engineered E.scherichia coli by Metabolic Engineering

So Young Choi1, KAIST Daeharkro 291, Daejeon, Republic of Korea
T: +82-42-350-5970, soyo466@kaist.ac.kr
Yu Kyung Jung1, KAIST
Si Jae Park2, Department of Environmental Engineering and Energy, Myongji University,San38-2,Nam- dong,Cheoin-gu,Yongin-si, Gyeonggido 449-728,Republic of Korea
Sang Yup Lee1, KAIST

1Department of Chemical & Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea, 2Department of Environmental Engineering and Energy, Myongji University, Yongin, South Korea

Polylactic acid (PLA) has been considered as a good alternative to petroleum-based plastic as it possesses several desirable properties such as biocompatibility, biodegradability, and compostability. However, current industrial PLA production depends on the two-step process: fermentative production of lactic acid (LA) followed by chemical polymerization with several catalysts. In this study, we were able to produce PLA and PLA- containing biopolymers using metabolically engineered E.scherichia coli. Introduction of the heterologous metabolic pathways involving engineered propionate CoA-transferase and polyhydroxyalkanoate synthase in wild-type E. coli resulted in synthesis of PLA and P(3-hydroxybutyrate-co-LA) [P(3HB-co-LA)] in E. coli. For further enhancement, the mMetabolic pathways of the E. coli strain were further engineered combined withbased on in silico genome-scale metabolic flux analysis. Using the metabolically resulting engineered strains, PLA homopolymer and P(3HB-co-LA) copolymers containing up to 70 mol% lactate could be produced up to 11 wt% and 46 wt% from glucose, respectively, from glucose. Thus, in this study, Tthe strategy of combined systems-level metabolic engineering and enzyme engineering in this study allowed efficient bio-based one-step production of PLA and its copolymers in E. coli. [â??This work was supported by the Technology Development Program to Solve Climate Changes from National Research Foundation of Korea (Development of systems metabolic engineering platform technologies for biorefineries; NRF-2012-C1AAA001-
2012M1A2A2026556) and Intelligent Synthetic Biology Center (2011-0031963) of Korea through the Global
Frontier Research Program of the Ministry of Education, Science and Technology (MEST).� ]

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