INTERNATIONAL JOURNAL OF ENERGY AND ENVIRONMENT Volume 2, Issue 3, 2011 pp.427-446 Journal homepage: www.IJEE.IEEFoundation.org ISSN 2076-2895 (Print), ISSN 2076-2909 (Online) ©2011 International Energy & Environment Foundation. All rights reserved. Assessment of pretreatments and enzymatic hydrolysis of wheat straw as a sugar source for bioprocess industry Bohdan Volynets, Yaser Dahman Department of Chemical Engineering, Ryerson University, Toronto, Ontario, Canada. Abstract Environmental concerns and rising oil prices have led to development of biofuels from crop residue lignocelluloses, among which wheat straw is an important feedstock used in leading commercial bioethanol processes. Lignocellulose is structured in a way that makes direct bioconversion of biomass into sugars by hydrolytic enzymes difficult and unfeasible, requiring a pretreatment step. Common biomass pretreatment technologies are assessed for potential application in obtaining fermentable sugars of wheat straw. Current outlook, challenges and opportunities on enzymatic hydrolysis of lignocellulose are also presented. Copyright © 2011 International Energy and Environment Foundation - All rights reserved. Keywords: Pretreatment, wheat straw, Enzymatic hydrolysis, Saccharification. 1. Introduction Industrial bioconversion of renewable resources is a promising alternative to petroleum-based chemical synthesis [1]. In this context, lignocellulosic biomass is an important renewable source of energy that has the potential to supply 20%-100% of the world’s total annual energy consumption [2]. Lignocellulose- based biorefineries are viewed as the trend of the future that would convert biomass into products falling into traditional petrochemical and future biobased markers [3]. Out of these products biofuels are of the utter most importance. In the United States, transportation biofuel production is currently dominated by first generation biofuels: maize grain ethanol and soybean biodiesel which are used as fuel additives and are short in supply [4]. Environmental and economic concerns associated with the use of fossil fuels have led to surge in development of second generation biofuels derived from lignocellulosic feedstock to transform transportation sector into a green infrastructure[4, 5]. Many feedstock are available for conversion such as crop residues (e.g. corn stover, wheat straw), dedicated energy crops (e.g. switch grass, poplar trees), forest residues (e.g. sawdust) and municipal solid waste (e.g. waste paper) [6, 7]. Among these, crop residues such as wheat straw and corn stover, and switch grass are thought to be of primary importance due to high availability and efficiency of conversion [8]. Lignocellulose feedstock biorefinery would consist of the four main stages: pretreatment, enzymatic hydrolysis, fermentation, and distillation. Besides feedstock, the costs of which can be minimized by focusing on agriculture residue, pretreatment to increase the susceptibility of biomass to enzymatic attack and enzymatic hydrolysis to release constituent sugars from biomass are the most expensive steps and require special attention [9]. Wheat straw has gained considerable utilization in commercial pilot plant bioethanol production [8, 10]. The purpose of this review is to examine the most common biomass pretreatment technologies with