In order to obtain a yeast strain which ferment starch into ethanol without saccharification, Commercial Baker's yeast Sacch. cerevisiae and Sacch. diaslaticus were selected as parntal strains for somatic fusion, Optimum conditions for the preparation...
In order to obtain a yeast strain which ferment starch into ethanol without saccharification, Commercial Baker's yeast Sacch. cerevisiae and Sacch. diaslaticus were selected as parntal strains for somatic fusion, Optimum conditions for the preparation, regeneration and fusion of yeast protoplasts were investigated.
The optimum conditions for preparation of yeast protoplasts were as follows:The concentration and the incubation time of lytic enzyme were 6 units and 60 min., respectively, in 100 mM 2mercaptoethanol. The initial number of cells was 1×??×??cells/ ml and the growth stage was late logarithmic phase. The concentration and the pH of osmotic stabilizer were 1.2M and 7.5, respectively. In these conditions, the protoplast yield was more than 90%.
The best regeneration of yeast protoplasts was obtained in 3% agar and M sorbitol.
In 40% polyethylene glycol(PEG 4000) and 10mM CaCl₂the fusion of yeast protoplasts appeared highest, and the fusion frequency marked 5.5∼5.9×??.