Bacterial Alpha-Amylase Inhibitors

Abstract

Summary The effect of 5 growth regulators at concentrations of 50, 100, and 1000 ppm on the activity of B. subtilis-37 alpha-amylase was studied. Indol butyric acid (IBA) did not inhibit alpha-amylase activity at concentrations of 50 to 1000 ppm. The other 4 growth regulators, 6-furfurylamino-purine, gibberellic acid, naphthalene acetic acid, and atonik-G, at all concentrations inhibited alpha-amylase activity. The effect of organic acids and formaldehyde at 0.01 M, 0.001 M, and 0.0005 M was studied. Acetic acid, oxalic acid, lactic acid, and malic acid at 0.01 M and 0.001 M caused 100 % inhibition of alpha-amylase, but at 0.0005 M the inhibitions were 14 %, 46 %, 12%, and 28%, respectively. Tartaric acid induced 100%, 85%, and 62% inhibition for alphaamylase at 0.01, 0.001, and 0.0005 M, respectively, but at the same concentration formaldehyde caused 60 %, 53 %, and 51 % inhibition. At 0.01 M concentration isopropanol, glycerol, and mannitol did not inhibit alpha-amylase activity. The inhibition percentages, caused by phenol, arabinose, lactose, maltose, galactose, ethanol, and sodium benzoate, were 13, 10, 8, 6, 6.5, and 4. Sorbitol, glucose, and fructose caused 3 % inhibition, while it was 2 % by sucrose at 0.01 M. But ammonium citrate dibasic at 0.01 M induced 60% inhibition for alpha-amylase activity. It was found that ZnSO4 and Fe2(SO4)3 were the strongest inhibitors, followed by SnCl2, Pb(C2H3O2)2, AgNO3, AlCl3, Cd(C2H3O2), CuCl2, FeSO4, HgCl2, and Na2-EDTA, in decreasing order. MnSO4 was a moderate inhibitor. The slight inhibitors in decreasing order were BaCl2, Co(NO3)2, Na2HPO4, NiSO4, and finally MgCl2.