Protoplast-fusion에 의한 澱粉에서 Ethanol의 單段 醱酵能 酵母 開發 : Ⅲ. Saccharomyces diastaticus로 부터 分離한 petite 變異株의 特性과 原形質體 融合 = Development of a New Yeast Fermenting Starch to Ethanol in Single Process by Protoplast-fusion

다국어 초록 (Multilingual Abstract)

Respiratory deficient mutant (petite) colonies of low sporulating Saccharomyces diastaticus were obtained after treatment with ethidium bromide (10㎍/ml) for a suitable fusant selection marker. The tetrazolium assay and the rate of oxygen uptake showed the respiratory deficiency of the isolated colonies. These colonies showed division slower rate than the parental cells, and not grow on nonfermentable carbon source such as glycerol that the parental cells readily utilize for growing. No revertant colonies were found on the minimal medium containing glycerol (MMG plate) The results obtained for ethanol productivity of glucose showed that the obtained petite mutants were similar to the parental strain. But the ability to assimilate and ferment starch were reduced by the induction of the petite mutants. These results sugges ted that thauptake and the utilization of starch should be affected by the mitiochondrial genome damaged by exposure to ethidium bromide. Protoplast formation, protoplast stability, and regeneration rate showed no difference between the parental strain and the petite strain. Thus using the characteristics of the petite strains as a marker for protoplast fusion, interspecific protoplast fusion between respiratory competent auxotrophic mutant strain of Sacch cerevisiae and repiratory deficient Strains of Sacch. diastaticvs were conducted. The respiratory competent starch fermenting fusion products could be selected on the minimal medium containing starch with low frequency. These were thought to be possible by mitochondrial transfer and recombination through protoplast fusion.