title: Carbon Flux Trapping: Highly Efficient Production of Polymer-Grade d-Lactic Acid with a Thermophilic d-Lactate Dehydrogenase.
abstract: High production of polymer-grade d-lactic acid is urgently required, particularly for the synthesis of polylactic acid. High-temperature fermentation has multiple advantages, such as lower equipment requirement and energy consumption, which are essential for lowering operating costs. We identified and introduced a unique d-lactate dehydrogenase into a thermotolerant butane-2,3-diol-producing strain. Carbon flux "trapping" was achieved by a "trapping point" created by combination of the introduced enzyme and the host efflux pump, which afforded irreversible transport of d-lactic acid. The overall carbon flux of the engineered strain was significantly enhanced and was redistributed predominantly to d-lactic acid. Under optimized conditions at 50 °C, d-lactic acid reached the highest titer (226.6 g L(-1) ) reported to date. This discovery allows us to extend the carbon flux trapping strategy to engineering complex metabolic networks.
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.|Joint International Research Laboratory of Metabolic, and Developmental Sciences, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.|Joint International Research Laboratory of Metabolic, and Developmental Sciences, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Tao
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China. pingxu@sjtu.edu.cn.|Joint International Research Laboratory of Metabolic, and Developmental Sciences, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China. pingxu@sjtu.edu.cn.|Shanghai Collaborative Innovation Center for Biomanufacturing, East China University of Science and Technology, 800 Dongchuan Road, Shanghai, 200237, China. pingxu@sjtu.edu.cn.
authors.forename: Ping
authors.initials: P
authors.lastname: Xu
mesh_terms: D057486:Carbon Cycle; D045022:Lactate Dehydrogenases / Q000737:chemistry / Q000378:metabolism*; D019344:Lactic Acid / Q000096:biosynthesis* / Q000737:chemistry; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors
chemical_list: D011108:Polymers; D019344:Lactic Acid; D045022:Lactate Dehydrogenases; C071195:D-lactate dehydrogenase
keywords: Bacillus licheniformis; biocatalysis; biosynthesis; lactate dehydrogenase; lactic acid; thermophile