Fu Gang, Zhang Shibin, Dong Huina, Chen Jingqi, Tu Ran, Zhang Dawei
Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China.
Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China.
Biotechnol Appl Biochem. 2020 Sep;67(5):812-818. doi: 10.1002/bab.1831. Epub 2019 Oct 29.
d-Psicose 3-epimerase is an enzyme that catalyzes the synthesis of d-psicose from d-fructose. We cloned the d-psicose 3-epimerase from Ruminococcus sp. (RDPE) and expressed it in Bacillus subtilis A311. By a two-step pH regulation of segmented fermentation, we significantly improved the RDPE production and decreased the fermentation cost. The two-step regulation consisted of the first step maintained the pH value at 7.0 for 24 H and the second step adjusted the pH value up to 7.5 slowly for another 24 H. Finally, the RDPE production was increased to 74 U/mL, which was about 2.5-fold compared with the control. Our segmented fermentation strategy provides an important experimental basis for the industrial-scale production of RDPE.
D-阿洛酮糖3-差向异构酶是一种催化由D-果糖合成D-阿洛酮糖的酶。我们从瘤胃球菌属克隆了D-阿洛酮糖3-差向异构酶（RDPE），并在枯草芽孢杆菌A311中进行表达。通过分段发酵的两步pH调节，我们显著提高了RDPE的产量并降低了发酵成本。两步调节包括第一步将pH值维持在7.0达24小时，第二步再将pH值缓慢调至7.5并持续24小时。最终，RDPE产量提高到74 U/mL，与对照相比约为2.5倍。我们的分段发酵策略为RDPE的工业化规模生产提供了重要的实验依据。
