Molecular cloning of fungal xylanases: an overview

Xylanases have received great attention in the development of environment-friendly technologies in the paper and pulp industry. Their use could greatly improve the overall lignocellulosic materials for the generation of liquid fuels and chemicals. Fungi are widely used as xylanase producers and are generally considered as more potent producers of xylanases than bacteria and yeasts. Large-scale production of xylanases is facilitated with the advent of genetic engineering. Recent breakthroughs in genomics have helped to overcome the problems such as limited enzyme availability, substrate scope, and operational stability. Genes encoding xylanases have been cloned in homologous and heterologous hosts with the objectives of overproducing the enzyme and altering its properties to suit commercial applications. Owing to the industrial importance of xylanases, a significant number of studies are reported on cloning and expression of the enzymes during the last few years. We, therefore, have reviewed recent knowledge regarding cloning of fungal xylanase genes into various hosts for heterologous production. This will bring an insight into the current status of cloning and expression of the fungal xylanases for industrial applications.