title: Construction of the industrial ethanol-producing strain of Saccharomyces cerevisiae able to ferment cellobiose and melibiose.
abstract: The gene mel1, encoding alpha-galactosidase in Schizosaccharomyces pombe, and the gene bgl2, encoding and beta-glucosidase in Trichoderma reesei, were isolated and co-expressed in the industrial ethanol-producing strain of Saccharomyces cerevisiae. The resulting strains were able to grow on cellobiose and melibiose through simultaneous production of sufficient extracellular alpha-galactosidase and beta-glucosidase activity. Under aerobic conditions, the growth rate of the recombinant strain GC 1 co-expressing 2 genes could achieve 0.29 OD600 h(-1) and a biomass yield up to 7.8 g l(-1) dry cell weight on medium containing 10.0 g l(-1) cellobiose and 10.0 g l(-1) melibiose as sole carbohydrate source. Meanwhile, the new strain of S. cerevisiae CG 1 demonstrated the ability to directly produce ethanol from microcrystalline cellulose during simultaneous saccharification and fermentation process. Approximately 36.5 g l(-1) ethanol was produced from 100 g of cellulose supplied with 5 g l(-1) melibose within 60 h. The yield (g of ethanol produced/g of carbohydrate consumed) was 0.44 g/g, which corresponds to 88.0% of the theoretical yield.
authors.affiliation: The Key Laboratory of Industrial Biotechnology, Ministry of Education, Center for Bioresources & Bioenergy, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China. biomass_jnu@126.com
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: Z P
authors.initials: ZP
authors.lastname: Guo
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Ding
authors.forename: Z X
authors.initials: ZX
authors.lastname: Wang
authors.forename: G Y
authors.initials: GY
authors.lastname: Shi
mesh_terms: D002475:Cellobiose / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005818:Genetic Engineering / Q000379:methods; D007218:Industrial Microbiology; D008553:Melibiose / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D012568:Schizosaccharomyces / Q000201:enzymology / Q000235:genetics; D014242:Trichoderma / Q000201:enzymology / Q000235:genetics; D000519:alpha-Galactosidase / Q000235:genetics / Q000378:metabolism*; D001617:beta-Glucosidase / Q000235:genetics / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D002475:Cellobiose; D000431:Ethanol; D008553:Melibiose; D001617:beta-Glucosidase; D000519:alpha-Galactosidase