1. Introduction
Xylan is an integral part of lignocellulosic structure, which is
the most abundant and renewable biomass available on earth [1].
It is an heterogeneous polysaccharide consisting of -1,4-linked
d-xylosyl residues along with a small fraction of arabinose, glucuronic
and arabinoglucuronic acids linked to the d-xylose back
bone [2]. Several industrial processes have been developed that
utilize agro-industrial biomass residues as raw materials for the
production of bulk chemicals such as ethanol and single-cell protein
and enzymes. In fact, use of agro-industrial residues in bioprocesses
is effective as alternative bio-substrates, and may reduce pollution
problems caused by their disposal [3]. Xylanases [EC.3.2.1.8] are
responsible for hydrolysis of xylan; they first attack the internal
main-chain linkages and subsequently releasing xylosyl residues
by endwise attack of xylooligosaccharides [4]. These enzymes have
recently attracted considerable attention due to their application
potential in hydrolysis or bioconversion of lignocelluloses to sugars.
In addition, xylanases also have application potential in industries
involved in clarification of juices, extraction of plant oils and
extracellular polymeric substances [EPS]. They have been known