Yeast In Yeast

Yeasts are single-cell eukaryotic microorganisms which classified in the kingdom of fungi and also gained a lot of importance in this era. Yeast can be naturally and widely found in nature such as soil, plants and many others (Jouhten et al., 2016). Yeast also plays role in fermentation process such as alcoholic beverages, bread and other industrial products. This is because yeast has metabolic activity that can be manipulated using genetic techniques, has higher biomass production and also generally recognize as safe organism (GRAS) (Thapa et al., 2015). However, instead of posses a good thing, yeast also can be responsible to infection and the most common yeast that cause the infection is the Candida albicans. The world famous yeast is Saccharomyces

The grape and pear fruits were set aside at dark place and room temperature for a few days to allow decaying process. After a few days, the grape and pear were squeezed to obtain the fermented juice of the fruit. Then 1 mL each of the juice was transferred into universal bottle to be diluted until 10-5. While for the dried fruit, the samples were crushed using mortar and pestle. 1 g of crushed sample was weighed and transferred into universal bottle and soaked with 5 mL peptone water to allow fermentation process. Then, 1mL of the dried fruit sample was diluted until 10-5 in the universal

After that, the media were allowed too cool at room temperature and poured into petri dishes.

c. Macroscopic identification

Yeast isolates were identified based on morphological characters. The morphology of the colonies were observed and compared with the positive control. The morphology of Saccharomyces cerevisiae shall be medium sized, flat, convex circular, smooth and cream in colour.

d. Microscopic identification

For the microscopic identification, the colonies that grew on the agar were observed thoroughly under microscope. The isolates are classified based on the morphology. Firstly, a drop of Indian ink was poured on the glass slide. Then a single colony on the agar was taken and mixed with the Indian ink and smeared on the slide. The slide was left to dry and ready to be viewed under microscope. The characteristic of Saccharomyces cerevisiae are spherical or oval shaped, reproduced by budding and no or simple pseudohyphae. To confirm this, the slide was compared with the positive control observation. This method was repeated several times with the colonies that grew on the media until found the matched