Cell Lysis Analysis of E.coli Expressing ScFv in Bioreactor

Abstract:

Cell lysis is a process problem in the protein expression using bacterial host. Under the same fermentation condition，the differences in the expression of foreign protein and cell activity between engineered and wild-type Escherichia coli W3110 expressed by the humanized single antibody fragments （ScFv） were studied. The results showed that high expression and accumulation of heterologous protein in the engineered E. coli cells were found，most living cells entered viable but nonculturable（VBNC） state 6 h in advance and the occurrence of cell lysis compared with wild-type. Thought the analysis of transcription levels of both E. coli c，we found that the process of ScFv expression causing overshoot phenomenon of multiple stressed responses pathway genes included rpoH，dnaK，dnaJ，groES，groEL in heat stress response pathway，rpoS，gadE，gadX in acid stress response pathway，sodA，katE in oxygen stress response patheway. However，during cell lysis process in the fermentation tank，the expression of membrane protein gene ompA，ompC，ompW，ompX was significantly decreased，but rpoE did not appear to continue to be high expression. These findings provide us new ideas to improve the resistance of engineering bacteria cells and control cells lysis.