Uncoupling growth and product formation kinetics to design improved strains for recombinant protein production in escherichia coli

The ability to control the synthesis of products in the absence of cell division remains an attractive alternative for the optimization of microbial processes. If this could be achieved, it would dramatically expand the productivity of many microbial processes by increasing product synthesis in the absence of an increase in cell mass. In the present work we have looked at the factors involved in the design of a host where the fluxes would be channeled towards product formation rather than biomass synthesis. To identify the genes responsible for diverting the metabolic flux specifically towards product formation we have used for this study is quiescent-cell (Q-cell) expression system, in which a plasmid-encoded protein is expressed in nongrowing but metabolically active cells. These cells channel the metabolic flux towards recombinant protein production and therefore the specific product yield per unit biomass is significantly higher. Indole which is previously known to be a signalling molecule is here used as an inducer of Quiescence. E.coli L-Asparaginase is used as a model protein in this work.

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