Production and optimization of xanthan gum from three-step sequential enzyme treated cassava bagasse hydrolysate

Xanthan gum was produced by microbial fermentation of enzyme hydrolyzed cassava bagasse. Cassava bagasse (CB) contains about 55-60% starch bound in a complex cellulose - hemicelluloses matrix. A mixture of pectinase and cellulase was used to release bound starch which was further hydrolyzed by alpha amylase and glucoamylase to recover maximum reducing sugar from CB. Up to 68% reducing sugars can be recovered from CB by this three step sequential enzyme hydrolysis. This was about 40% higher than that obtained by the acid hydrolysis. Cassava Bagasse hydrolysate (CBH) obtained after enzyme hydrolysis was used for xanthan gum production using Xanthamonas campestris NCIM 2956. Inoculum size, initial sugar concentration, nitrogen source and C/N ratio were optimized for xanthan gum production using enzyme CBH. Xanthan gum obtained was characterized using H-1 NMR, FTIR, and gel filtration chromatography. Under optimized conditions, xanthan gum yield obtained from enzyme treated CBH was 0.469 g xanthan gum/g CB.