Production and application of thermostable cellulase-free xylanase by aspergillus fumigatus from agricultural wastes

Abstract

Xylan is a principal structural component in plant cell walls and could interfere in many industries and biological activities. Biosynthesis of the xylan-degrading enzyme xylanase by fungal isolates was investigated, using agricultural wastes as substrates for production. Aspergillus fumigatus was shown to be the superior isolate to produce xylanase, and wheat bran proved to be the most appropriate substrate for enzyme production and activity. Media composition and growth conditions were optimized for the production of fungal xylanase using Plackett-Burman multifactorial mixture design and Box-Behnken experimental design. Characterization of the purified xylanase revealed that the most favorable conditions for the maximum enzyme activity (57IU/mL) were temperature of 55-60°C with thermal stability for 30min and pH of 9 with enzyme stability for 20min. Application of xylanase for biodegradation of sugarcane pulp fibers was examined using scanning electron micrographs, which exhibited a vigorous alteration in the topography of fiber surface and structure with a prolonged enzymatic treatment period. © 2012, Mary Ann Liebert, Inc.