Application of pigeon pea (Cajanus cajan) stalks as raw material for xylooligosaccharides production

Pigeon pea (Cajanus cajan) is a perennial plant widely cultivated in tropical and subtropical regions of many countries. The present studies aimed to produce xylooligosaccharides (XOS) from pigeon pea stalks in order to do value addition. The chemical analysis of stalks revealed 18.33 ± 1.40 % hemicelluloses in addition to cellulose, protein, and lignin. Sodium hydroxide coupled with steam application enabled almost 96 % recovery of original xylan, present in the pigeon pea stalks. Enzymatic hydrolysis of xylan led to production of XOS namely, xylobiose and xylotriose. Response surface model indicated a maximum yield of xylobiose (0.502 mg/ml) under the hydrolysis conditions of pH 4.91, temperature at 48.11 °C, enzyme dose at 11.01 U, and incubation time at 15.65 h. The ideal conditions for higher xylotriose yield (0.204 mg/ml) were pH 5.44, temperature at 39.29 °C, enzyme dose at 3.23 U, and incubation time at 15.26 h. The present investigation was successful in assessing the prospect of using pigeon pea stalks as a raw material for xylan extraction vis-à-vis XOS production.