| Summary: | 碩士 === 國立屏東科技大學 === 食品科學系 === 89 === The study was tryied to breed the yeast which could assimilation or fermentation the starch by the technique of cell fusion. The fusion was carried out between the protoplast of Schizosaccharomyces pombe and the chloroplast of plant ٠ the protoplast of Schiz. pombe and the protoplast of Monascus anka ٠ the protoplast of Schiz. pombe and the protoplast of Saccharomyces diastaticus or the protoplast of Schiz. pombe and the protoplast of fusant.
The cell wall lytic enzyme was prepared by the complex medium of sawdust and bran (1:1) cultivated Trichoderma viride for 8 days, then the enzyme was extracted by the 90mL of 50mM phosphate buffer contained 0.4M KCl (pH 5.5). Cell of Schiz. pombe ٠ M. anka ٠ S. diastaticus and fusant could obtain their protoplasts by reacted with the cell wall lytic enzyme solution at 40ºC,50rpm.
The desirable fusants with different characteristics by protoplast fusion were isolated. Fusant 1, Fusant 2, Fsuant 3 and Fusant 4 were isolated from fusion between Schiz. pombe and chloroplast , the Fusant 5 and Fusant 6 were from Schiz. pombe and M. anka, the Fusant 7 was from Schiz. pombe and S. diastaticus ,the Fusant 8 was from Schiz. pombe and fusant.
By the protoplast fusion, fusants were increased their
assimilation ability of carbon compounds, such as galactose, L-sorbose, cellobiose, trehalose, melibiose, inulin, citric acid and starch. Fusants were also increased the assimilation ability of hydroncarbon compounds, such as n-pentane, n-heptane, hexane, n-octane and kerosene. Fusant 5 and fusant6 obtained the ability to ferment the starch, and their fermentative were better then S. diastaticus. Their fermentation ability of the other fusants were also changed. The yeast extract and beef extract were found as a good nitrogen source for fusants. The good growth were also found included of 2% starch, 1% yeast extract, pH 4~6 in the medium, and were cultured at 30ºC.
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