Optimization of xylanase production by newly isolated strain Trichoderma afroharzianum isolate AZ 12 in solid state fermentation using response surface methodology

Abstract

Xylanases are hydrolytic enzymes with wide applications in several industries, such as biofuels, paper, deinking, food and feed. Response surface methodology and Box-Behnken matrix were used to optimize the culture conditions for xylanase production by Trichoderma afroharzianum isolate AZ 12 in solid state fermentation using wheat bran as substrate. The influence of four variables was examined in this research, namely incubation time, humidity, temperature and inoculum size. The analysis of variance was applied and xylanase production was expressed with a mathematical equation as a function of the factors. The optimal conditions for xylanase production were obtained as follows: 6 days of fermentation, humidity of 85%, incubation temperature of 22 °C and inoculum size of 1.9 × 107spores/mL - under such conditions, xylanase activity increased from 8475.87 to 14766.28 U/mL. Experimental design has proven to be an effective method for determining the optimal parameters for enzyme production.