title: Direct fermentation of amorphous cellulose to ethanol by engineered Saccharomyces cerevisiae coexpressing Trichoderma viride EG3 and BGL1.
abstract: Direct ethanol fermentation from amorphous cellulose was achieved using an engineered industrial Saccharomyces cerevisiae strain. Two cellulase genes endoglucanase (eg3) and β-glucosidase (bgl1) were obtained from Trichoderma viride and integrated into the genome of S. cerevisiae. These two cellulases could be constitutively coexpressed and secreted by the recombinant strain S. cerevisiae-eb. The enzyme activities were analyzed in the culture supernatants, with the highest endoglucanase activity of 2.34 units/ml and β-glucosidase activity of 0.95 units/ml. The effects of pH, temperature and metal ions on enzyme activities were analyzed. The coexpression strain S. cerevisiae-eb could grow in carboxymethyl cellulose (CMC) and utilize it as the single carbon source. The 20 g/L CMC as a model substrate of amorphous cellulose was used in fermentation. The ethanol production reached 4.63 g/L in 24 h, with the conversion ratio of 64.2% compared with the theoretical concentration. This study demonstrated that the engineered industrial strain S. cerevisiae-eb could convert amorphous cellulose to ethanol simultaneously and achieve consolidated bioprocessing (CBP) directly.
authors.forename: Yingxue
authors.initials: Y
authors.lastname: Gong
authors.forename: Genyun
authors.initials: G
authors.lastname: Tang
authors.forename: Mingming
authors.initials: M
authors.lastname: Wang
authors.forename: Jingbo
authors.initials: J
authors.lastname: Li
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Xiao
authors.forename: Jianghai
authors.initials: J
authors.lastname: Lin
authors.forename: Zehuan
authors.initials: Z
authors.lastname: Liu
mesh_terms: D002480:Cellulase / Q000235:genetics / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D060847:Metabolic Engineering; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D013696:Temperature; D014242:Trichoderma / Q000201:enzymology / Q000235:genetics; D001617:beta-Glucosidase / Q000235:genetics / Q000378:metabolism*
chemical_list: D003470:Culture Media; D011994:Recombinant Proteins; D000431:Ethanol; D002482:Cellulose; D001617:beta-Glucosidase; D002480:Cellulase