Streptococcus zooepidemicus A TCC 35246, an organism acquired from American Type Culture Collection was capable of producing hyaluronic acid at 180.23 mg/ml. Upon exposing to UV-light for 80120 seconds for 3 rounds, a mutant designated CU 47 capable of producing hyaluronic acid at 370.13 mgll was obtained. Further mutation via NTG ( N.-m ethyl-N'-nitro-N-nitrosoguanidine) at 50 Jlg/ml, 5-40 minutes, 37 ·C yielded a number of mutants producing hyaluronic acid in higher yield. Subsequent isolation and mutation via NTG for 4 additional rOlll1ds, a mutant namely CUN5-10 was obtained with ability of producing hyaluronic acid at 585.85 mgll. Optimal conditions for hyaluronic acid production by CUN5-10 were : cultivation at room temperature (28-32 ·C) , initial pH of7.5, initial concentration of sucrose at 10 gil with agitation rate of 200 rpm. Under such conditions CUN 5-10 could produce hyaluronic acid at 829.11 mg/l.
