Energetic benefits and rapid cellobiose fermentation by Saccharomyces cerevisiae expressing cellobiose phosphorylase and mutant cellodextrin transporters
메타 데이터
바이오화학분류
바이오플라스틱
플라스틱
바이오정밀화학
용매
화학제품
연료
화장품용 기능성소재
계면활성제⁄증점제
의료용 화학소재
식품첨가제
논문
Energetic benefits and rapid cellobiose fermentation by Saccharomyces cerevisiae expressing cellobiose phosphorylase and mutant cellodextrin transporters
학술지
Metabolic engineering
저자명
Ha, S.J.; Galazka, J.M.; Joong Oh, E.; Kordic, V.; Kim, H.; Jin, Y.S.; Cate, J.H.D.
초록
Anaerobic bacteria assimilate cellodextrins from plant biomass by using a phosphorolytic pathway to generate glucose intermediates for growth. The yeast Saccharomyces cerevisiae can also be engineered to ferment cellobiose to ethanol using a cellodextrin transporter and a phosphorolytic pathway. However, strains with an intracellular cellobiose phosphorylase initially fermented cellobiose slowly relative to a strain employing an intracellular β-glucosidase. Fermentations by the phosphorolytic strains were greatly improved by using cellodextrin transporters with elevated rates of cellobiose transport. Furthermore under stress conditions, these phosphorolytic strains had higher biomass and ethanol yields compared to hydrolytic strains. These observations suggest that, although cellobiose phosphorolysis has energetic advantages, phosphorolytic strains are limited by the thermodynamics of cellobiose phosphorolysis (ΔG<SUP>o</SUP>=+3.6kJmol<SUP>-1</SUP>). A thermodynamic ''push'' from the reaction immediately upstream (transport) is therefore likely to be necessary to achieve high fermentation rates and energetic benefits of phosphorolysis pathways in engineered S. cerevisiae.