This study is the first to use CaCl2 as a stimulator in c-PGA biosynthesis. Our results show that c-PGA biosynthesis can be controlled with CaCl2, by reducing viscosity of culture broth or
enhancing glutamate synthetic flux through changes in key enzymes (ICDH, GDH, and ODHC) around the 2-oxoglutarate branch,
and that molecular weight of c-PGA remains essentially constant
regardless of the amount of CaCl2 added. This effect of exogenous
CaCl2 contributes to redistribution of metabolic flux and improved
c-PGA production in B. subtilis.