title: Repeated-batch fermentation of lignocellulosic hydrolysate to ethanol using a hybrid Saccharomyces cerevisiae strain metabolically engineered for tolerance to acetic and formic acids.
abstract: A major challenge associated with the fermentation of lignocellulose-derived hydrolysates is improved ethanol production in the presence of fermentation inhibitors, such as acetic and formic acids. Enhancement of transaldolase (TAL) and formate dehydrogenase (FDH) activities through metabolic engineering successfully conferred resistance to weak acids in a recombinant xylose-fermenting Saccharomyces cerevisiae strain. Moreover, hybridization of the metabolically engineered yeast strain improved ethanol production from xylose in the presence of both 30 mM acetate and 20mM formate. Batch fermentation of lignocellulosic hydrolysate containing a mixture of glucose, fructose and xylose as carbon sources, as well as the fermentation inhibitors, acetate and formate, was performed for five cycles without any loss of fermentation capacity. Long-term stability of ethanol production in the fermentation phase was not only attributed to the coexpression of TAL and FDH genes, but also the hybridization of haploid strains.
authors.affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Sanda
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Hasunuma
authors.forename: Fumio
authors.initials: F
authors.lastname: Matsuda
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kondo
mesh_terms: D019342:Acetic Acid / Q000378:metabolism*; D000222:Adaptation, Physiological; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005561:Formates / Q000378:metabolism*; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism*; D060847:Metabolic Engineering; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000502:physiology
chemical_list: D005561:Formates; C030544:formic acid; C036909:lignocellulose; D000431:Ethanol; D008031:Lignin; D019342:Acetic Acid