Ma Weichao, Cao Weijia, Zhang Hong, Chen Kequan, Li Yan, Ouyang Pingkai
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816, People's Republic of China,
Biotechnol Lett. 2015 Apr;37(4):799-806. doi: 10.1007/s10529-014-1753-5. Epub 2014 Dec 17.
The effect of fusing the PelB signal sequence to lysine/cadaverine antiporter (CadB) on the bioconversion of L-lysine to cadaverine was investigated. To construct a whole-cell biocatalyst for cadaverine production, four expression plasmids were constructed for the co-expression of lysine decarboxylase (CadA) and lysine/cadaverine antiporter (CadB) in Escherichia coli. Expressing CadB with the PelB signal sequence increased cadaverine production by 12%, and the optimal expression plasmid, pETDuet-pelB-CadB-CadA, contained two T7 promoter-controlled genes, CadA and the PelB-CadB fusion protein. Based on pETDuet-pelB-CadB-CadA, a whole-cell system for the bioconversion of L-lysine to cadaverine was constructed, and three strategies for L-lysine feeding were evaluated to eliminate the substrate inhibition problem. A cadaverine titer of 221 g l(-1) with a molar yield of 92% from lysine was obtained.
研究了将PelB信号序列与赖氨酸/尸胺反向转运蛋白（CadB）融合对L-赖氨酸生物转化为尸胺的影响。为构建用于生产尸胺的全细胞生物催化剂，构建了四个表达质粒，用于在大肠杆菌中共表达赖氨酸脱羧酶（CadA）和赖氨酸/尸胺反向转运蛋白（CadB）。用PelB信号序列表达CadB可使尸胺产量提高12%，最佳表达质粒pETDuet-pelB-CadB-CadA包含两个由T7启动子控制的基因，即CadA和PelB-CadB融合蛋白。基于pETDuet-pelB-CadB-CadA构建了一个将L-赖氨酸生物转化为尸胺的全细胞系统，并评估了三种L-赖氨酸进料策略以消除底物抑制问题。获得了221 g l(-1)的尸胺效价，基于赖氨酸的摩尔产率为92%。
