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. 1986 Feb;51(2):362–367. doi: 10.1128/aem.51.2.362-367.1986

Construction of Lactose-Assimilating and High-Ethanol-Producing Yeasts by Protoplast Fusion

F Farahnak 1, T Seki 1,†, Dewey D Y Ryu 1,*, D Ogrydziak 1
PMCID: PMC238874  PMID: 16346992

Abstract

The availability of a yeast strain which is capable of fermenting lactose and at the same time is tolerant to high concentrations of ethanol would be useful for the production of ethanol from lactose. Kluyveromyces fragilis is capable of fermenting lactose, but it is not as tolerant as Saccharomyces cerevisiae to high concentrations of ethanol. In this study, we have used the protoplast fusion technique to construct hybrids between auxotrophic strains of S. cerevisiae having high ethanol tolerance and an auxotrophic strain of lactose-fermenting K. fragilis isolated by ethyl methanesulfonate mutagenesis. The fusants obtained were prototrophic and capable of assimilating lactose and producing ethanol in excess of 13% (vol/vol). The complementation frequency of fusion was about 0.7%. Formation of fusants was confirmed by the increased amount of chromosomal DNA per cell. Fusants contained 8 × 10−8 to 16 × 10−8 μg of DNA per cell as compared with about 4 × 10−8 μg of DNA per cell for the parental strains, suggesting that multiple fusions had taken place.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Anne J., Eyssen H., De Somer P. Somatic hybridisation of Penicillium roquefortii with P. chrysogenum after protoplast fusion. Nature. 1976 Aug 19;262(5570):719–721. doi: 10.1038/262719a0. [DOI] [PubMed] [Google Scholar]
  2. Anné J., Peberdy J. F. Conditions for induced fusion of fungal protoplasts in polyethylene glycol solutions. Arch Microbiol. 1975 Nov 7;105(3):201–205. doi: 10.1007/BF00447138. [DOI] [PubMed] [Google Scholar]
  3. BURTON K. A study of the conditions and mechanism of the diphenylamine reaction for the colorimetric estimation of deoxyribonucleic acid. Biochem J. 1956 Feb;62(2):315–323. doi: 10.1042/bj0620315. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Dickson R. C. Expression of a foreign eukaryotic gene in Saccharomyces cerevisiae: beta-galactosidase from Kluyveromyces lactis. Gene. 1980 Sep;10(4):347–356. doi: 10.1016/0378-1119(80)90155-9. [DOI] [PubMed] [Google Scholar]
  5. Ferenczy L., Kevei F., Zsolt J. Fusion of fungal protoplasts. Nature. 1974 Apr 26;248(5451):793–794. doi: 10.1038/248793a0. [DOI] [PubMed] [Google Scholar]
  6. Ferenczy L., Maráz A. Transfer of mitochondria by protoplast fusion in Saccharomyces cerevisiae. Nature. 1977 Aug 11;268(5620):524–525. doi: 10.1038/268524a0. [DOI] [PubMed] [Google Scholar]
  7. HUTCHISON W. C., MUNRO H. N. The determination of nucleic acids in biological materials. A review. Analyst. 1961 Dec;86:768–813. doi: 10.1039/an9618600768. [DOI] [PubMed] [Google Scholar]
  8. Langer P. R., Waldrop A. A., Ward D. C. Enzymatic synthesis of biotin-labeled polynucleotides: novel nucleic acid affinity probes. Proc Natl Acad Sci U S A. 1981 Nov;78(11):6633–6637. doi: 10.1073/pnas.78.11.6633. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Leary J. J., Brigati D. J., Ward D. C. Rapid and sensitive colorimetric method for visualizing biotin-labeled DNA probes hybridized to DNA or RNA immobilized on nitrocellulose: Bio-blots. Proc Natl Acad Sci U S A. 1983 Jul;80(13):4045–4049. doi: 10.1073/pnas.80.13.4045. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Mahoney R. R., Nickerson T. A., Whitaker J. R. Selection of strain, growth conditions, and extraction procedures for optimum production of lactase from Kluyveromyces fragilis. J Dairy Sci. 1975 Nov;58(11):1620–1629. doi: 10.3168/jds.S0022-0302(75)84760-6. [DOI] [PubMed] [Google Scholar]
  11. Sheetz R. M., Dickson R. C. Mutations affecting synthesis of beta-galactosidase activity in the yeast Kluyveromyces lactis. Genetics. 1980 Aug;95(4):877–890. doi: 10.1093/genetics/95.4.877. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Sipiczki M., Ferenczy L. Protoplast fusion of Schizosaccharomyces pombe Auxotrophic mutants of identical mating-type. Mol Gen Genet. 1977 Feb 28;151(1):77–81. doi: 10.1007/BF00446915. [DOI] [PubMed] [Google Scholar]
  13. van Solingen P., van der Plaat J. B. Fusion of yeast spheroplasts. J Bacteriol. 1977 May;130(2):946–947. doi: 10.1128/jb.130.2.946-947.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]

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