Optimization of solid-state fermentation parameters for the production of xylanase by Trichoderma longibrachiatum on wheat bran in a forced aeration system

The effect of aeration an the production of xylanase by Trichoderma longibr achiatum on wheat bran in a solid-state fermentation (SSF) system has not b een investigated. This study was conducted to investigate the interactive e ffects of aeration, initial moisture content of the substrate, and depth of the substrate on xylanase activity produced in a tray fermenter The experi ment was conducted as a split plot experiment with factorial treatments and three replications of each treatment combination. The whole plot treatment was aeration rate (0, 2.9, 5.7 L/min/kg bran). Initial moisture content (4 5, 55, 65% w.b.) and depth of substrate (1.0 and 2.5 cm) were investigated factorially. Trays of wheat bran were assayed after fermentation by Trichod erma longibrachiatum to determine the production of xylanase activity. Aera tion rate had a significant nonlinear effect on enzyme activity with highes t yields obtained at an aeration rate of 2.9 L/min/kg bran (738 U/g, averag ed over all initial moisture contents and depth of substrates). Initial moi sture content of the substrate also had a significant nonlinear effect an e nzyme activity with the highest yields at 55% (556 U/g, averaged over all a irflow rates and depths of substrate). Depth of substrate had no significan t statistical effect on enzyme activity. The treatment combination of 2.9 L /min/kg airflow rate and 55% moisture content resulted in the highest yield s (948 U/g, averaged over depth of substrate).