title: Chemo-enzymatic production of fuel ethanol from cellulosic materials utilizing yeast expressing beta-glucosidases.
abstract: Ethanol was produced in a considerably high yield by fermenting hydrolyzates from cellulosic materials by means of a recombinant laboratory yeast expressing beta-glucosidases. Tissue paper, cotton, and sawdust were hydrolyzed by two-step sulfuric acid hydrolysis to give mixtures containing glucose, cellobiose, and higher cello-oligosaccharides. After the cellulosic material was partially hydrolyzed with 80% sulfuric acid, the hydrolysis was continued with 5% sulfuric acid. Except for non-carbohydrate components, all constituents in the hydrolyzates were fermented by the yeast that was preincubated in the medium that the plasmid encoded by the beta-glucosidases gene was kept in the multiplicated yeast. A solution containing 4% hydrolyzates from paper was fermented to give as high as 1.9% maximum ethanol concentration and 70% ethanol conversion. Cotton also gave a similar result. Sawdust was converted into ethanol in approx 22% conversion. Accordingly, it was revealed that the beta-glucosidases-expressing yeast can ferment the cello-oligosaccharides obtained by hydrolysis of cellulosic materials into ethanol. In addition, a hydrolyzate containing a high glucose proportion gave a high ethanol concentration in a short time.
authors.affiliation: Department of Environmental and Material Engineering, Teikyo University of Science and Technology, 2525 Yatsusawa, Uenohara, Yamanashi 409-0193, Japan. uryu@ntu.ac.jp
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Uryu
authors.forename: Masashi
authors.initials: M
authors.lastname: Sugie
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ishida
authors.forename: Shinya
authors.initials: S
authors.lastname: Konoma
authors.forename: Hironori
authors.initials: H
authors.lastname: Kato
authors.forename: Kaname
authors.initials: K
authors.lastname: Katsuraya
authors.forename: Kohsaku
authors.initials: K
authors.lastname: Okuyama
authors.forename: Gereltu
authors.initials: G
authors.lastname: Borjihan
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Iwashita
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Iefuji
mesh_terms: D001230:Aspergillus / Q000201:enzymology; D001709:Biotechnology / Q000379:methods*; D002241:Carbohydrates / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D002482:Cellulose / Q000737:chemistry*; D004736:Energy-Generating Resources; D000431:Ethanol / Q000737:chemistry*; D005285:Fermentation; D005742:Gasoline; D005947:Glucose / Q000378:metabolism; D006868:Hydrolysis; D008956:Models, Chemical; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013464:Sulfuric Acids / Q000737:chemistry; D001617:beta-Glucosidase / Q000096:biosynthesis* / Q000737:chemistry
chemical_list: D002241:Carbohydrates; D005742:Gasoline; D013464:Sulfuric Acids; D000431:Ethanol; D002244:Carbon; D002482:Cellulose; D001617:beta-Glucosidase; D005947:Glucose; C033158:sulfuric acid