Functional Assembly of Minicellulosomes on the <i>Saccharomyces cerevisiae</i> Cell Surface for Cellulose Hydrolysis and Ethanol Production
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- Shen-Long Tsai
- Department of Chemical and Environmental Engineering, University of California at Riverside, Riverside, California 92521
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- Jeongseok Oh
- Department of Chemical and Environmental Engineering, University of California at Riverside, Riverside, California 92521
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- Shailendra Singh
- Department of Chemical and Environmental Engineering, University of California at Riverside, Riverside, California 92521
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- Ruizhen Chen
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Dr. NW, Atlanta, Georgia 30032-0100
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- Wilfred Chen
- Department of Chemical and Environmental Engineering, University of California at Riverside, Riverside, California 92521
説明
<jats:title>ABSTRACT</jats:title> <jats:p> We demonstrated the functional display of a miniscaffoldin on the <jats:italic>Saccharomyces cerevisiae</jats:italic> cell surface consisting of three divergent cohesin domains from <jats:italic>Clostridium thermocellum</jats:italic> (t), <jats:italic>Clostridium cellulolyticum</jats:italic> (c), and <jats:italic>Ruminococcus flavefaciens</jats:italic> (f). Incubation with <jats:italic>Escherichia coli</jats:italic> lysates containing an endoglucanase (CelA) fused with a dockerin domain from <jats:italic>C. thermocellum</jats:italic> (At), an exoglucanase (CelE) from <jats:italic>C. cellulolyticum</jats:italic> fused with a dockerin domain from the same species (Ec), and an endoglucanase (CelG) from <jats:italic>C. cellulolyticum</jats:italic> fused with a dockerin domain from <jats:italic>R. flavefaciens</jats:italic> (Gf) resulted in the assembly of a functional minicellulosome on the yeast cell surface. The displayed minicellulosome retained the synergistic effect for cellulose hydrolysis. When a β-glucosidase (BglA) from <jats:italic>C. thermocellum</jats:italic> tagged with the dockerin from <jats:italic>R. flavefaciens</jats:italic> was used in place of Gf, cells displaying the new minicellulosome exhibited significantly enhanced glucose liberation and produced ethanol directly from phosphoric acid-swollen cellulose. The final ethanol concentration of 3.5 g/liter was 2.6-fold higher than that obtained by using the same amounts of added purified cellulases. The overall yield was 0.49 g of ethanol produced per g of carbohydrate consumed, which corresponds to 95% of the theoretical value. This result confirms that simultaneous and synergistic saccharification and fermentation of cellulose to ethanol can be efficiently accomplished with a yeast strain displaying a functional minicellulosome containing all three required cellulolytic enzymes. </jats:p>
収録刊行物
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- Applied and Environmental Microbiology
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Applied and Environmental Microbiology 75 (19), 6087-6093, 2009-10
American Society for Microbiology