Engineering Thermostable Microbial Xylanases Toward its Industrial Applications

Xylanases are one of the important hydrolytic enzymes which hydrolyze the β-1, 4 xylosidic linkage of the backbone of the xylan polymeric chain which consists of xylose subunits. Xylanases are mainly found in plant cell walls and are produced by several kinds of microorganisms such as fungi, bacteria, yeast, and some protozoans. The fungi are considered as most potent xylanase producers than that of yeast and bacteria. There is a broad series of industrial applications for the thermostable xylanase as an industrial enzyme. Thermostable xylanases have been used in a number of industries such as paper and pulp industry, biofuel industry, food and feed industry, textile industry, etc. The present review explores xylanase-substrate interactions using gene-editing tools toward the comprehension in improvement in industrial stability of xylanases. The various protein-engineering and metabolic-engineering methods have also been explored to improve operational stability of xylanase. Thermostable xylanases have also been used for improvement in animal feed nutritional value. Furthermore, they have been used directly in bakery and breweries, including a major use in paper and pulp industry as a biobleaching agent. This present review envisages some of such applications of thermostable xylanases for their bioengineering.