Purification and characterization of Rhizoctonia solani AG-4 strain ZB-34 α-amylase produced by solid-state fermentation using corn bran

Abstract

Abstract Background Aim of the study was to produce α-amylase cheaply from Rhizoctonia solani AG-4 strain ZB-34 by solid-state fermentation and investigate its suitability for some industries. Methods Rhizoctonia solani AG-4 strain ZB-34 α-amylase was purified with starch affinity method. Results The best production of enzyme was achieved by using corn bran. Optimum pH and temperature were 5.5 and 50°C, respectively. V max and K 0.5 were determined as 238.8 U/mg protein and 0.03% from substrate-activity curve. Activity was maintained about 100% in the tested pHs after 1 day incubation. The enzyme conserved full of its activity at 4 and 28°C for 120 min. Mn2+, Ca2+, Tween 20, Triton X-100 and Triton X-114 activated the enzyme. The enzyme was highly active in the presence of some commercial detergents. The chocolate stains on the cotton fabrics were more effectively cleaned with the combination of a commercial detergent and purified enzyme. The purified enzyme also clarified the raw apple juice and desized the cotton fabrics. Conclusion The results showed that Rhizoctonia solani AG-4 strain ZB-34 α-amylase might have potential application as a detergent additive. In addition, its activity between pH 4.0 and 7.0 may facilitate its use in the food and fruit processing industries.