High-level exogenous glutamic acid-independent production of poly-(γ-glutamic acid) with organic acid addition in a new isolated Bacillus subtilis C10

► A new glutamic acid-independent γ-PGA producing strain was isolated. ► This strain was characterized as Bacillus subtilis C10. ► Citric acid and oxalic acid showed capability to support γ-PGA overproduction in C10. ► The activities of four key intracellular enzymes were measured. ► Oxalic acid enhanced the activity of pyruvate dehydrogenase.