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. 2008 Sep;9(9):1621-1651.
doi: 10.3390/ijms9091621. Epub 2008 Sep 1.

Pretreatment of lignocellulosic wastes to improve ethanol and biogas production: a review

Mohammad J Taherzadeh  1 , Keikhosro Karimi  1   2
Affiliations

Pretreatment of lignocellulosic wastes to improve ethanol and biogas production: a review

Mohammad J Taherzadeh et al. Int J Mol Sci. 2008 Sep.

Abstract

Lignocelluloses are often a major or sometimes the sole components of different waste streams from various industries, forestry, agriculture and municipalities. Hydrolysis of these materials is the first step for either digestion to biogas (methane) or fermentation to ethanol. However, enzymatic hydrolysis of lignocelluloses with no pretreatment is usually not so effective because of high stability of the materials to enzymatic or bacterial attacks. The present work is dedicated to reviewing the methods that have been studied for pretreatment of lignocellulosic wastes for conversion to ethanol or biogas. Effective parameters in pretreatment of lignocelluloses, such as crystallinity, accessible surface area, and protection by lignin and hemicellulose are described first. Then, several pretreatment methods are discussed and their effects on improvement in ethanol and/or biogas production are described. They include milling, irradiation, microwave, steam explosion, ammonia fiber explosion (AFEX), supercritical CO(2) and its explosion, alkaline hydrolysis, liquid hot-water pretreatment, organosolv processes, wet oxidation, ozonolysis, dilute-and concentrated-acid hydrolyses, and biological pretreatments.

Keywords: Pretreatment; biodegradation; biogas; ethanol; lignocellulose; methane; waste.

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Figures

Figure 1.
Figure 1.
Pretreatment of lignocellulosic materials prior to bioethanol and biogas production
Figure 2.
Figure 2.
Effect of pretreatment on accessibility of degrading enzymes
See this image and copyright information in PMC

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