الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Cellulosic and/or hemicellulosic materials such as wood agricultural wastes and municipal wastes can be enzymatically hydrolysed to yield glucose and xylose. These sugars can be fermented to a variety of biotechnical products in a separate process or simultaneously with enzymatic hydrolysis. Most cellulosic materials contain three major organic components: cellulose, hemicellulose and lignin. The composition varies depending on the source of the material and a corresponding variation is known in the ease of hydrolysis of these materials. In wood the cellulose content is about 40% and an economical utilization is not possible if hemicellulose (30%) and lignin (20-30%) is not utilized. In hardwood the hemicellulose is mainly made up of xylan which can be relatively easily hydroloysed to xylose. The hydrolysis of xylan can be accomplished either by a chemical treatment such as mild acid hydrolysis or steam treatment or by enzymatic hydrolysis. Enzymes hydrolysing xylan are produced by many organisms, e.g., Trichoderma reesei, Aspergillus foetitius, A. niger and Bacillus subtilis. Xylose can be utilized for the manufacture of furfural or xylitol. It can also be used as a nutrient in the cultivation of fodder yeast. In softwood the hemicellulose consists mainly of glucomannan, which after hydrolysis can be fermented together with the glucose.: produced from cellulose . The hydrolysis of glucomannan is possible with the aid of hydrolytic enzymes produced certain microorganisms.