LS-8-P-3175 Microscopic morphology of ascospore of thermotolerant yeast, UBU-strains

Yeast is an eukaryotic microorganism. Yeast’s cell is spherical, oval or lemon shape. The diameter of yeast’s cell is around 5 µm. Asexual reproduction of yeast is budding. Some species of yeast reproduce sexual stage by mating of two compatible haploid cells. After fusion of cytoplasm, the mated cell becomes diploid cell. Then diploid cell divides by meiosis into four haplYeast is an eukaryotic microorganism. Yeast’s cell is spherical, oval or lemon shape. The diameter of yeast’s cell is around 5 µm. Asexual reproduction of yeast is budding. Some species of yeast reproduce sexual stage by mating of two compatible haploid cells. After fusion of cytoplasm, the mated cell becomes diploid cell. Then diploid cell divides by meiosis into four haploid cell. Haploid cell develops to be ascospore or basidiospore depend upon its genetic material. Ascospore will be formed in the ascus or sac. We had isolated the new strains of thermotolerant yeast that can produce ethanol. We also identified them by their morphology and biochemical characters. The characteristics of ascospore such as shape, size, color, decoration and number of ascospore per ascus, are essential for identification the sample into species. The experiment inducing ascospore-formation was conducted for the required stage. The optimal condition was found to be cultivation on V-8 juice medium at pH 7 under 25 degree celcius. 23 out of 25 isolates could produce ascospore in above condition. Then the microscopic morphology of thermotolerant yeast, UBU-strains at their ascospore-formation stage was revealed by light microscope and scanning electron microscope. Two out of 23 isolates, UBU-1-11 and UBU-2-16 produced ascospores as shown in fig 1 and fig 2. The microscopic morphology of the thermotolerant yeast at vegetative stage and sexual stage will be described in details.