Authors: Sutanu Samanta Asitava Basu Umesh Chandra Halder Soumitra Kumar Sen
Publish Date: 2012/06/30
Volume: 50, Issue: 3, Pages: 518-525
Abstract
The endoglucanase II of Trichoderma reesei is considered the most effective enzyme for biofinishing cotton fabrics and biostoning denim garments However the commercially available preparation of endoglucanase II is usually mixed with other cellulase components especially endoglucanase I resulting in hydrolysis and weight loss of garments during biofinishing and biostoning We thus isolated the endoglucanase II gene from T reesei to express this in Pichia pastoris under the control of a methanolinducible AOX1 promoter to avoid the presence of other cellulase components A highly expressible Mut+ transformant was selected and its expression in BMMH medium was found most suitable for the production of large amounts of the recombinant protein Recombinant endoglucanase II was purified to electrophoretic homogeneity and functionally characterized by activity staining The specific activity of recombinant endoglucanase II was found to be 22057 EU/mg of protein Purified recombinant endoglucanase II was estimated to have a molecular mass of 528 kDa The increase in molecular mass was likely due to hyperglycosylation Hyperglycosylation of recombinant endoglucanase II secreted by P pastoris did not change the temperature or pH optima as compared to the native protein but did result in increased thermostability Kinetic analysis showed that recombinant endoglucanase was most active against amorphous cellulose such as carboxymethyl cellulose for which it also had a high affinity
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