Produksi dan Karakterisasi Enzim Tanin Asil Hidrolase dari Aspergillus niger.

Abstract

Tannin acyl hydrolase (tannase) is a hydrolytic enzyme that acts on tannins. The application of tannase is mostly in food and medical industries. This research is aimed to produce and characterize tannase from Aspergillus niger isolated from pod cacao. The first step of this research includes determination of optimal pH, temperature and incubation period to produce tannase. Optimal tannase production was obtained at pH 5.5, 28 oC and incubation period of 3 days. Afterthat, production media optimization was conducted. The tested media were solid and liquid media with inducer concentration varied at 0, 3, 5 and 7%. The best media obtained was the solid media with tannic acid concentration as inducer of 5%. The next step was tannase fractionation by ammonium sulphate which was followed by dialysis process. The saturation le vel of ammonium sulphate used was 30-80% where the best activity obtained was at the saturation level of 60%. Compared to that of crude enzyme, specific activity of tannase after dialysis was four folds. Characterization results showed that optimum activity was at 35-50 oC and pH 6. Tannase was activated by K+ and Na+ with concentration of 10 and 50 mM, while Mg2+ ion could activate only at 10 mM. The addition metal ions like Zn2+, Cu2+, Ca2+, Mn2+ and Fe2+ inhibited the enzyme activity. From test of variation of substrate, it was found that the Km value of tannic acid and gallotannin was 0.401 and 6.611 mM respectively. While the Vmax value of tannic acid was 10.804 U/ml and gallotannin was 12.406 U/ml. Based on the Michaelis- Menten constant (Km), tannase of obtained in this research was more active in hydrolysing depsid bonds rather than ester bonds.