Universal Growth Switch for Two-Stage Bioprocess in Bacteria

Fast-growing bacteria spare little resources for product production whereas highly productive strains grow slowly. This growth - production tradeoff limits the productivity of many processes in industrial biotechnology. Two-stage bioprocess is a workaround to this dilemma - at first, cells are grown with maximum speed without significant product production, then the growth is switched off and all available resources are channelled to product synthesis. Switching off growth while leaving cellular metabolism active is not an easy task and existing solutions are usually specific to each product. Here we describe a novel universal growth switch of bacteria that allows to stop their growth at any given culture density. The switch is carried out by removing oriC from E. coli genome using site-specific recombinases. This prevents any further initiation of genome replication, as a result cells stop their growth, but retain active metabolism. We demonstrate that in the switched cells the expression of protein of interest is increased several times and also the period of metabolic activity is significantly longer as compared to control cells. This technology has the potential to increase the productivity of many processes in industrial biotechnology and the prospect to make production of several products economically feasible.