Extremophilic Bacterial Xylanases: Production, Characteristics and Applications

Abstract

Xylan is the most abundant polysaccharide among hemicelluloses and it has a linear backbone of β-1, 4-linked D-xylopyranose residues. Complete biodegradation of xylan into constituent sugars requires the action of several xylanolytic enzymes. A wide variety of microbes produces xylanolytic enzymes in order to achieve xylan hydrolysis. Immense interest in the enzymatic hydrolysis of xylan is due to its multiple applications. The thermo-alkali-stable xylanases have potential applications in pulping and bleaching processes, food and feed industry, textile processing, enzymatic saccharification of lignocellulosic materials and waste treatment. Most of the available commercial xylanases are from mesophilic microbes, which fail to function at alkaline pH and elevated temperatures prevailing in industrial processes. Alkaliphilic and thermophilic bacteria are very important sources of xylanases with the desirable twin characteristics of thermostability and alkalistability, and therefore, very important in developing environment-friendly pulp bleaching process.