Thermodynamics characterization and potential textile applications of Trichoderma longibrachiatum KT693225 xylanase

Our study was a trial to participate in solving two main problems namely, environmental pollution resulting from accumulation and bad disposal of agro-industrial wastes, and high cost of industrial xylanase enzyme production. This was achieved through successful xylanase production by solid-state fermentation of low cost disposable agricultural wastes by marine fungal isolate Trichoderma longibrachiatum KT693225. The highest xylanase production 7.13 +/- 0.11 U ml(-1) was obtained utilizing rice straw (RS) waste after 7days of fermentation. Xylanase was purified by fractional precipitation with ethanol causing 4.24-fold purification. The 75% ethanol fraction was rich in cellulase, pectinase and alpha-amylase enzymes beside xylanase. The maximal xylanase activity was obtained at 60 degrees C, pH 5% and 2.5% xylan concentration. The K-m and V-max were calculated to be 20 mg ml(-1) and 20 mu mol min(-1) ml(-1), respectively. The thermostability of T.longibrachiatum KT693225 xylanase was indicated by low E-a (activation energy)and high E-d (energy of denaturation). High T-1/2 (half life), D-value (decimal reduction time), Delta H degrees (enthalpy), Delta G degrees (free energy) and low K-d (denaturation rate constant), Delta S degrees (entropy) values at 70 degrees C emphasized high T. longibrachiatum KT693225 xylanase stability. T. longibrachiatum KT693225 xylanase showed high effectiveness at several textile wet-processing stages including desizing, bioscouring and biofinishing of cellulosic fabrics without adding any additives. These findings in this study have great implications for the future applications of xylanases.