Department of Biological Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China.
Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, People's Republic of China.
J Ind Microbiol Biotechnol. 2019 Jun;46(6):793-800. doi: 10.1007/s10295-019-02159-5. Epub 2019 Mar 12.
Pseudomonas putida was metabolically engineered to produce medium chain length polyhydroxyalkanoate (mcl-PHA) from acetate, a promising carbon source to achieve cost-effective microbial processes. As acetate is known to be harmful to cell growth, P. putida KT2440 was screened from three Pseudomonas strains (P. putida KT2440, P. putida NBRC14164, and P. aeruginosa PH1) as the host with the highest tolerance to 10 g/L of acetate in the medium. Subsequently, P. putida KT2440 was engineered by amplifying the acetate assimilation pathway, including overexpression of the acs (encoding acetyl-CoA synthetase) route and construction of the ackA-pta (encoding acetate kinase-phosphotransacetylase) pathway. The acs overexpressing P. putida KT2440 showed a remarkable increase of mcl-PHA titer (+ 92%), mcl-PHA yield (+ 50%), and cellular mcl-PHA content (+ 43%) compared with the wild-type P. putida KT2440, which indicated that acetate could be a potential substrate for biochemical production of mcl-PHA by engineered P. putida.
铜绿假单胞菌被代谢工程改造为能够利用乙酸生产中链长度聚羟基烷酸（mcl-PHA），乙酸是一种很有前途的碳源，可以实现具有成本效益的微生物工艺。由于已知乙酸对细胞生长有害，因此从三种假单胞菌菌株（铜绿假单胞菌 KT2440、铜绿假单胞菌 NBRC14164 和铜绿假单胞菌 PH1）中筛选出对培养基中 10 g/L 乙酸具有最高耐受性的铜绿假单胞菌 KT2440 作为宿主。随后，通过扩增乙酸同化途径对铜绿假单胞菌 KT2440 进行了工程改造，包括过表达 acs（编码乙酰辅酶 A 合成酶）途径和构建 ackA-pta（编码乙酸激酶-磷酸转乙酰酶）途径。与野生型铜绿假单胞菌 KT2440 相比，acs 过表达的铜绿假单胞菌 KT2440 的 mcl-PHA 产量（+92%）、mcl-PHA 得率（+50%）和细胞内 mcl-PHA 含量（+43%）均显著增加，这表明乙酸可以作为工程化铜绿假单胞菌生产 mcl-PHA 的潜在生物化学底物。
