title: Creation of an ethanol-tolerant yeast strain by genome reconstruction based on chromosome splitting technology.
abstract: We sought to breed an industrially useful yeast strain, specifically an ethanol-tolerant yeast strain that would be optimal for ethanol production, using a novel breeding method, called genome reconstruction, based on chromosome splitting technology. To induce genome reconstruction, Saccharomyces cerevisiae strain SH6310, which contains 31 chromosomes including 12 artificial mini-chromosomes, was continuously cultivated in YPD medium containing 6% to 10% ethanol for 33 days. The 12 mini-chromosomes can be randomly or specifically lost because they do not contain any genes that are essential under high-level ethanol conditions. The strains selected by inducing genome reconstruction grew about ten times more than SH6310 in 8% ethanol. To determine the effect of minichromosome loss on the ethanol tolerance phenotype, PCR and Southern hybridization were performed to detect the remaining mini-chromosomes. These analyses revealed the loss of mini-chromosomes no. 11 and no. 12. Mini-chromosome no. 11 contains ten genes (YKL225W, PAU16, YKL223W, YKL222C, MCH2, FRE2, COS9, SRY1, JEN1, URA1) and no. 12 contains fifteen genes (YHL050C, YKL050W-A, YHL049C, YHL048C-A, COS8, YHLComega1, ARN2, YHL046W-A, PAU13, YHL045W, YHL044W, ECM34, YHL042W, YHL041W, ARN1). We assumed that the loss of these genes resulted in the ethanol-tolerant phenotype and expect that this genome reconstruction method will be a feasible new alternative for strain improvement.
authors.affiliation: Department of Biomaterial Control (BK 21 program), Dong-Eui University, Busan 614-714, Korea.
authors.forename: A-Hwang
authors.initials: AH
authors.lastname: Park
authors.forename: Minetaka
authors.initials: M
authors.lastname: Sugiyama
authors.forename: Satoshi
authors.initials: S
authors.lastname: Harashima
authors.forename: Yeon-Hee
authors.initials: YH
authors.lastname: Kim
mesh_terms: D015825:Chromosomes, Fungal; D004361:Drug Tolerance; D000431:Ethanol / Q000378:metabolism* / Q000633:toxicity*; D017353:Gene Deletion; D005827:Genetics, Microbial / Q000379:methods*; D007218:Industrial Microbiology / Q000379:methods; D060847:Metabolic Engineering / Q000379:methods*; D008967:Molecular Biology / Q000379:methods; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*
chemical_list: D000431:Ethanol