Value addition of cotton stalks through enzymatic production of xylooligosaccharides

摘要

The present work focuses on the value addition of cotton stalks through xylan extraction and enzymatic production of xylooligosaccharides (XOS); a pentose based prebiotic. Chemical analysis revealed that cotton stalk contains neutral detergent fibre 87.66%, acid detergent fibre 72.81%, hemicellulose 14.85%, cellulose 53.08%, and acid detergent lignin 19.73%. The xylan yield from cotton stalks was ranged from 1.75 to 7.36% when recovered with lithium hydroxide, while it reached up to 14% by using sodium and potassium hydroxides. The maximum recovery of xylan was attained at 4% NaOH together with steam and 8% KOH under overnight incubation. Commercial xylanase enzyme was used for enzymatic hydrolysis of xylan to produce XOS. The XOS concentration was ranged from 0.83 to maximum value of 2.19 mg/ml in the hydrolysate at pH 5.0, enzyme dose of 5 U, for 4 h of hydrolysis time. The findings substantiated the potentiality of cotton stalk as a raw material for xylan extraction vis a vis production of XOS.