1. Introduction
Renewable fuels from fermentation of biomass (e.g. bioethanol
from lignocellulosic agricultural residue) are considered as potential
alternatives to conventional energy sources like fossil fuels. In
fact, conversion of lignocellulosic biomass to bioethanol presents a
practical option for improving energy security and reducing greenhouse
gas emissions. Agricultural residues (e.g. wheat straw, rice
straw and sugarcane bagasse) and forest products (wood chips
and sawdust) are renewable, cheap and worldwide accessible and
because they are non-food sources, their vast conversion to biofuels
does not affect the food security [1].
Lignocelluloses are mainly composed of cellulose, hemicellulose
and lignin which have been naturally developed to block their
deconstruction from microbes and enzymes, defined as “biomass
recalcitrance” [2]. Lignin is a complex, hydrophobic, cross-linked,
aromatic polymer composed of phenylpropanoid units. It works as
an adhering agent which tangles with cellulose and hemicellulose
and protects them against degradation. Therefore, delignification