State Key Laboratory of Food Nutrition and Safety, Tianjin University of Science and Technology, Tianjin, 300457, PR China.
Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin, 300457, PR China.
Curr Microbiol. 2021 Jul;78(7):2640-2647. doi: 10.1007/s00284-021-02510-z. Epub 2021 May 15.
In this study, the strain Streptomyces diastatochromogenes 6#-7, which efficiently synthesizes ε-Poly-L-lysine, was studied and the effects of 18 amino acids and overexpression of dapA gene on the fermentation efficiency of ε-PL by S. diastatochromogenes were investigated. It was shown that L-proline, L-lysine, L-isoleucine, and L-threonine could promote the production of ε-PL. Moreover, the overexpression of the dihydrodipicolinate synthase gene (dapA) helped improve the fermentation performance of S. diastatochromogenes. The maximum ε-PL yield of the overexpressing strain (S. diastatochromogenes 12#-2) increased by 17.5% compared with the original strain in 500 mL shake flask. When the fermentation was conducted in a 5-L fermenter, the fermentation duration was extended by 48 h, and ε-PL yield reached 30.54 g/L, which was a 19.8% increase compared to the original strain. The results of this study offered a promising approach to augment the production of ε-PL from Streptomyces, thus paving the way to reduce the cost of product ε-PL and enhance the fermentation efficiency of ε-PL production.
在这项研究中，研究了能够高效合成ε-聚赖氨酸的链霉菌（Streptomyces diastatochromogenes）6#-7 菌株，并考察了 18 种氨基酸和 dapA 基因过表达对 S. diastatochromogenes 发酵生产 ε-PL 的效率的影响。结果表明，L-脯氨酸、L-赖氨酸、L-异亮氨酸和 L-苏氨酸可以促进 ε-PL 的生产。此外，二氢二羧酸合酶基因（dapA）的过表达有助于提高链霉菌 diastatochromogenes 的发酵性能。与原始菌株相比，过表达菌株（S. diastatochromogenes 12#-2）的 ε-PL 最大产量在 500 mL 摇瓶中提高了 17.5%。当在 5-L 发酵罐中进行发酵时，发酵时间延长了 48 h，ε-PL 产量达到 30.54 g/L，与原始菌株相比提高了 19.8%。这项研究的结果为提高链霉菌 ε-PL 的产量提供了一种有前景的方法，从而降低产品 ε-PL 的成本并提高 ε-PL 生产的发酵效率。
