title: Co-expression of TAL1 and ADH1 in recombinant xylose-fermenting Saccharomyces cerevisiae improves ethanol production from lignocellulosic hydrolysates in the presence of furfural.
abstract: Lignocellulosic biomass dedicated to bioethanol production usually contains pentoses and inhibitory compounds such as furfural that are not well tolerated by Saccharomyces cerevisiae. Thus, S. cerevisiae strains with the capability of utilizing both glucose and xylose in the presence of inhibitors such as furfural are very important in industrial ethanol production. Under the synergistic conditions of transaldolase (TAL) and alcohol dehydrogenase (ADH) overexpression, S. cerevisiae MT8-1X/TAL-ADH was able to produce 1.3-fold and 2.3-fold more ethanol in the presence of 70 mM furfural than a TAL-expressing strain and a control strain, respectively. We also tested the strains' ability by mimicking industrial ethanol production from hemicellulosic hydrolysate containing fermentation inhibitors, and ethanol production was further improved by 16% when using MT8-1X/TAL-ADH compared to the control strain. Transcript analysis further revealed that besides the pentose phosphate pathway genes TKL1 and TAL1, ADH7 was also upregulated in response to furfural stress, which resulted in higher ethanol production compared to the TAL-expressing strain. The improved capability of our modified strain was based on its capacity to more quickly reduce furfural in situ resulting in higher ethanol production. The co-expression of TAL/ADH genes is one crucial strategy to fully utilize undetoxified lignocellulosic hydrolysate, leading to cost-competitive ethanol production.
authors.affiliation: Organization of Advanced Science and Technology, 1-1 Rokkodai-cho, Nada, Kobe 657-8501, Japan. Electronic address: hasunuma@port.kobe-u.ac.jp.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Hasunuma
authors.affiliation: School of Bioprocess Engineering, Universiti Malaysia Perlis, Kompleks Pusat Pengajian Jejawi 3, Arau, 02600 Perlis, Malaysia; Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501, Japan. Electronic address: kusyahidah@unimap.edu.my.
authors.forename: Ku Syahidah Ku
authors.initials: KSK
authors.lastname: Ismail
authors.affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501, Japan. Electronic address: nambu@people.kobe-u.ac.jp.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Nambu
authors.affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501, Japan. Electronic address: akondo@kobe-u.ac.jp.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kondo
mesh_terms: D000426:Alcohol Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D056804:Biofuels / Q000032:analysis / Q000600:supply & distribution; D000431:Ethanol / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D005285:Fermentation / Q000187:drug effects; D005662:Furaldehyde / Q000378:metabolism* / Q000494:pharmacology; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism*; D010427:Pentose Phosphate Pathway / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014153:Transaldolase / Q000235:genetics / Q000378:metabolism*; D059467:Transcriptome / Q000187:drug effects / Q000235:genetics; D014994:Xylose / Q000378:metabolism*
chemical_list: D056804:Biofuels; D029701:Saccharomyces cerevisiae Proteins; C036909:lignocellulose; D000431:Ethanol; D008031:Lignin; D014994:Xylose; D005662:Furaldehyde; C516801:ADH1 protein, S cerevisiae; D000426:Alcohol Dehydrogenase; D014153:Transaldolase; C587993:TAL1 protein, S cerevisiae
keywords: ADH1; Bioethanol; Furfural; Hemicellulosic hydrolysate; Overexpression; Saccharomyces cerevisiae; TAL1; Xylose