Extracellular α-Galactosidase from Trichoderma sp. (WF-3): Optimization of Enzyme Production and Biochemical Characterization

Trichoderma spp. have been reported earlier for their excellent capacity of secreting extracellular α-galactosidase. This communication focuses on the optimization of culture conditions for optimal production of enzyme and its characterization. The evaluation of the effects of different enzyme assay parameters such as stability, pH, temperature, substrate concentrations, and incubation time on enzyme activity has been made. The most suitable buffer for enzyme assay was found to be citrate phosphate buffer (50 mM, pH 6.0) for optimal enzyme activity. This enzyme was fairly stable at higher temperature as it exhibited 72% activity at 60°C. The enzyme when incubated at room temperature up to two hours did not show any significant loss in activity. It followed Michaelis-Menten curve and showed direct relationship with varying substrate concentrations. Higher substrate concentration was not inhibitory to enzyme activity. The apparent Michaelis-Menten constant (K m ), maximum rate of reaction (V max), K cat, and catalytic efficiency values for this enzyme were calculated from the Lineweaver-Burk double reciprocal plot and were found to be 0.5 mM, 10 mM/s, 1.30 U mg(-1), and 2.33 U mg(-1) mM(-1), respectively. This information would be helpful in understanding the biophysical and biochemical characteristics of extracellular α-galactosidase from other microbial sources.