Development of Sucrose-Fermenting Escherichia Coli K-12 Strains for Low- Cost Overproduction of Recombinant Proteins

摘要

Escherichia coli K-l2 strains were the most widely used microorganisms for carrying out genetic engineering experiments. During the past two decades, the E. coli K-12 host has been routinely used for production of a variety of substances on the industrial scale. E. coli K-12 strains do not have the sucrose fermenting capacity that other industrially useful microorganisms have. Therefore, the use of relatively inexpensive raw materials (e.g., molasses) in the fermentation process is not feasible. Sucrose fermenting E. coli K-l2 strains could substantially reduce the cost of recombinant protein production. A two-plasmid system was successfully engineered to render E. coli K-l2 sucrose-positive. In addition, high level recombinant target protein production was achievable with invertase containing strains grown on sucrose. Expression of recombinant PEP-C was compared in this strain grown on the three different media. PEP-C expression in cells grown on sucrose only was either comparable to or better than expression observed in cells grown either on glucose or in rich medium. These experiments demonstrated high level recombinant target protein production in an E. coli K-l2 strain grown on sucrose as the sole carbon source in the growth medium.