title: Bioethanol production from cellulosic hydrolysates by engineered industrial Saccharomyces cerevisiae.
abstract: Even though industrial yeast strains exhibit numerous advantageous traits for the production of bioethanol, their genetic manipulation has been limited. This study demonstrates that an industrial polyploidy Saccharomyces cerevisiae JHS200 can be engineered through Cas9 (CRISPR associated protein 9)-based genome editing. Specifically, we generated auxotrophic mutants and introduced a xylose metabolic pathway into the auxotrophic mutants. As expected, the engineered strain (JX123) enhanced ethanol production from cellulosic hydrolysates as compared to other engineered haploid strains. However, the JX123 strain produced substantial amounts of xylitol as a by-product during xylose fermentation. Hypothesizing that the xylitol accumulation might be caused by intracellular redox imbalance from cofactor difference, the NADH oxidase from Lactococcus lactis was introduced into the JX123 strain. The resulting strain (JX123_noxE) not only produced more ethanol, but also produced xylitol less than the JX123 strain. These results suggest that industrial polyploidy yeast can be modified for producing biofuels and chemicals.
authors.affiliation: Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Ye-Gi
authors.initials: YG
authors.lastname: Lee
authors.affiliation: Department of Food Science and Human Nutrition, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Yong-Su
authors.initials: YS
authors.lastname: Jin
authors.affiliation: Bioenergy Crop Research Institute, National Institute of Crop Science, Rural Development Administration, Muan 58545, Republic of Korea.
authors.forename: Young-Lok
authors.initials: YL
authors.lastname: Cha
authors.affiliation: Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Seoul National University, Seoul 151-921, Republic of Korea. Electronic address: jhseo94@snu.ac.kr.
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Seo
mesh_terms: D056804:Biofuels / Q000382:microbiology*; D019149:Bioreactors / Q000382:microbiology; D002482:Cellulose / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D006868:Hydrolysis; D007218:Industrial Microbiology; D008031:Lignin / Q000378:metabolism; D060847:Metabolic Engineering / Q000379:methods*; D009097:Multienzyme Complexes / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000302:isolation & purification / Q000378:metabolism*; D014994:Xylose / Q000378:metabolism
chemical_list: D056804:Biofuels; D009097:Multienzyme Complexes; C036909:lignocellulose; D000431:Ethanol; D002482:Cellulose; D008031:Lignin; D014994:Xylose; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases
keywords: Cas9 genome editing; Hydrolysate fermentation; Industrial Saccharomyces cerevisiae; Lignocellulosic ethanol