Enhancing the light-driven production of D-lactate by engineering cyanobacterium using a combinational strategy.
It is increasingly attractive to engineer cyanobacteria for bulk production of chemicals from CO2. However, cofactor bias of cyanobacteria is different from bacteria that prefer NADH, which hampers cyanobacterial strain engineering. In this study, the key enzyme d-lactate dehydrogenase (LdhD) from Lactobacillus bulgaricus ATCC11842 was engineered to reverse its favored cofactor from NADH to NADPH. Then, the engineered enzyme was introduced into Synechococcus elongatus PCC7942 to construct an efficient light-driven system that produces d-lactic acid from CO2. Mutation of LdhD drove a fundamental shift in cofactor preference towards NADPH, and increased d-lactate productivity by over 3.6-fold. We further demonstrated that introduction of a lactic acid transporter and bubbling CO2-enriched air also enhanced d-lactate productivity. Using this combinational strategy, increased d-lactate concentration and productivity were achieved. The present strategy may also be used to engineer cyanobacteria for producing other useful chemicals.
State Key Laboratory of Microbial Metabolism, and School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
Chao
C
Li
State Key Laboratory of Microbial Metabolism, and School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
Fei
F
Tao
State Key Laboratory of Microbial Metabolism, and School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
Jun
J
Ni
State Key Laboratory of Microbial Metabolism, and School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
Yu
Y
Wang
State Key Laboratory of Microbial Metabolism, and School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
Feng
F
Yao
State Key Laboratory of Microbial Metabolism, and School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
Ping
P
Xu
D020650:Combinatorial Chemistry Techniques / Q000379:methods; D003198:Computer Simulation; D024861:Genetic Enhancement / Q000379:methods*; D019344:Lactic Acid / Q000096:biosynthesis* / Q000302:isolation & purification; D008027:Light; D008957:Models, Genetic; D009097:Multienzyme Complexes / Q000235:genetics*; D010788:Photosynthesis / Q000502:physiology* / Q000528:radiation effects; D011994:Recombinant Proteins / Q000235:genetics; D046940:Synechococcus / Q000502:physiology* / Q000528:radiation effects; D015854:Up-Regulation / Q000502:physiology / Q000528:radiation effects
D009097:Multienzyme Complexes; D011994:Recombinant Proteins; D019344:Lactic Acid