Improving the production of S-adenosyl-L-methionine in Escherichia coli by overexpressing metk |
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Authors: | Ping Yu Pengzhi Zhu |
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Institution: | College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang Province, People’s Republic of China |
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Abstract: | S-adenosyl-L-methionine (SAM) has important applications in many fields including chemical therapy and pharmaceutical industry. In this study, the recombinant Escherichia coli strain was constructed for effective production of SAM by introducing the SAM synthase gene (metK). This strain produced 34.5?mg/L of SAM in basic medium in shake flask. Yeast extract, pH, and loaded volume had a significant positive effect on the yield of SAM. Their optimal values were 35?g/L, 7.5, and 30?mL, respectively. The final conditions optimized were as follows: glucose 20, g/L; peptone, 40?g/L; yeast extract, 35?g/L; NaCl, 10?g/L; MgSO4, 1.2?g/L; L-methionine, 1?g/L; rotate speed, 220?rpm; loaded volume, 30?mL; inoculation, 1%; temperature, 37°C; and initial medium, pH 7.5. The recombinant strain produced 128.2?mg/L of SAM under the above conditions in shake flask. The production of SAM in a 5?L fermentor was also investigated. The maximal biomass of the recombinant strain was 60.4?g/L after the cells were cultured for 20?hr, and the highest yield of SAM was 300.9?mg/L after induction for 8?hr in a 5?L fermentor. This study provides a good foundation for the future production and use of SAM. |
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Keywords: | Optimization overexpression recombinant E coli response surface methodology L-methionine" target="_blank">S-adenosyl-L-methionine SAM synthase |
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