Role of microbial xylanases in biorefinery platform and its impact on ecosystem services

Xylan is the second most abundant naturally occurring renewable polysaccharide available on earth. The breakdown of xylan is restricted due to its heterogeneous nature, and it can be overcome by xylanases capable of cleaving the heterogeneous β-1,4-glycoside linkage. Xylan is a polysaccharide made from β1,4-linked xylose (pentose sugar) residues with the branches at the side of α-arabinofuranose and α-glucuronic acid with cellulose microfibrils mediated by ferulic acid residues. The application of xylanase enzymes produced from low-cost agricultural substrates such as rice straw, wheat straw, microalgae, and other wastes produced by sub-merged and solid-state fermentation was found to have a promising future in biorefining.