PRODUÇÃO E CARACTERIZAÇÃO FÍSICO-QUÍMICA DE XILANASES PRODUZIDAS POR Trichoderma viride

Abstract

The xylanases are hydrolases which depolymerize the xylan components present in the plants cell walls. Applications include use in the pulp and paper industries, food, animal feed, textiles, among others. This study is the first report about the extracellular xylanase production using pineapple peel as substrate by a Trichoderma viride strain and optimizes their production. Additionally, the xylanases produced were biochemically characterized. The xylanase activity was determined according to 3,5-dinitrosalicylic acid (DNS) method, using xylose as standard. The protein was determined by modified Bradford method, using bovine serum albumin as standard. Pineapple peel was the agro-industrial waste that induced higher xylanase production at 2% concentration, for seven days, in stationary cultivation at 28ºC, in pH 7.5. Xylanases were more active at 50ºC, pH 6.0, remaining stable at pH 5.0-5.5 (93.8% and 85.25% of residual activity, respectively). T. viride xylanase was stable at 40°C, showing the half-life (T1/2) value of 255 min. The enzyme was remarkably stimulated by Mg²+ and Zn²+, while Pb3+ and Hg²+ were strong inhibitors of the xylanase activity. This work shows the ability of the filamentous fungus T. viride to grow on the agro-industrial waste pineapple peel and produce high levels of xylanases. The enzymes produced are promising for industrial application, mainly in process that cellulases are undesirable, such as pulp, paper and textile industries.