Fig. 4.

Schematic of possible synthetic BMC functions in metabolic engineering. The semipermeable shell allows a substrate to diffuse into the lumen that is then processed by enzyme A. The intermediate (red) can be a toxin that needs to be contained, an unstable molecule that requires fast processing, or a metabolite that can be used by off-branching metabolic pathways. In all these cases encapsulation of the enzymes into a BMC would eliminate such problems. Enzyme B can be a promiscuous or slow enzyme, operating more efficiently when given only one specific substrate in high concentrations. The shell also can act to stabilize proteins by preventing proteolytic degradation and decouples the pathway from endogenous regulation by preventing inhibitors from accessing the encapsulated enzymes