Enhanced plasmid stability and production of hEGF by immobilized recombinant E. coli JM101

Recombinant Escherichia coli JM101 was immobilized with porous polyurethane foam (PUF) particle as supporter matrix for human epidermal growth factor (hEGF) production. Flask culture showed that cell immobilization in PUF can improve cell growth and hEGF expression. A bubble column and a three-phase fluidized bed bioreactor by self-design was further applied to produce hEGF, respectively. The results demonstrated that PUF is a feasible immobilized supporter material with good biocompatibility. Immobilization could also decrease the probability for segregational plasmid loss and overgrowth of plasmid-free cells. Cell density, plasmid stability and hEGF productivity were higher than those without the foam matrix, respectively. hEGF productivity was enhanced from 8.73 mg/l h of free-culture to 11.4 mg/l h of immobilized cultivation.