Can the excretion of metabolites by bacteria be manipulated?

Bacteria can release metabolites into the environment by various mechanisms. Excretion may occur by passive diffusion or by the reversal of the uptake process when the internal concentration of the metabolite exceeds the thermodynamic equilibrium level. In other cases, solutes are excreted against the concentration gradient by special extrusion systems. Their mode of energy coupling is different to that of the well-studied group of uptake systems. A thorough understanding of the transport processes will help to improve the excretion of metabolites of commercial interest, allow a more efficient production of metabolites in bulk quantities, and permit their exploitation to establish new markets.