Reutealis trisperma Press Cake Induced Production of Xylanase by Trichoderma reesei: Effect of C/N Ratio and Initial pH

摘要

Reutealis trisperma plant is widely used for nature conservation and the oil seeds have been studied for biodiesel production. The press cake is a solid waste which contains 34.03% protein, 18.56% total sugar, 15.58% lipid, 6.32% moisture and 25.51% others. Since its high content of protein, the cake is used as additional nitrogen source for xylanase production using Trichoderma reesei. Xylanase has a wide range of applications such as in pre-bleaching of pulp, improving the digestibility of animal feed stocks, bioconversion of lignocellulosic material to fermentable products and clarification of fruit juices. In pulp and paper industries, pre-bleaching of pulp by xylanase can save 35-40% of chlorine used which would reduce the potential hazard to environment. T. reesei is a mesophyllic, filamentous fungus which has been well studied for its ability to produce extracellular enzymes capable of degrading cell wall polysaccharides. The aims of the study are: 1) to formulate media at various C/N ratio in defined medium and various initial pH, and to formulate media containing ground press cake at both optimum C/N ratio and initial pH from defined medium. 2) to calculate xylanase activity in both media. In this study, T.reesei was cultivated in shake flask at 28°C in defined medium at various C/N ratio and initial pH and in the culture medium contained ground press cake at optimum C/N ratio and initial pH. The defined medium composition contained cellulose as carbon source at various concentration; organic and inorganic nitrogen sources and mineral salts. Ground cake was used to replace some inorganic nitrogen used in defined medium for media containing ground cake. Sample was withdrawn periodically to measure the pH and xyalanse activity. The best C/N ratio and initial pH in defined medium were 7.8/1 and 6.0 respectively which resulted in 66.93 U/mL of xylanase activity. The xylanase activity was 30.75 U/mL in media containing ground press cake.