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 α-amylase enzymes beside xylanase. The maximal xylanase activity was obtained at 60 °C, pH 5% and 2.5% xylan concentration. The Km and Vmax were calculated to be 20 mg ml−1 and 20 µmol min−1 ml−1, respectively. The thermostability of T.longibrachiatum KT693225 xylanase was indicated by low Ea (activation energy)and high Ed (energy of denaturation). High T1/2 (half life), D-value (decimal reduction time), ΔH° (enthalpy), ΔG° (free energy) and low Kd (denaturation rate constant), ΔS° (entropy) values at 70 °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.