Determination of fermentative properties of yeast strains isolated from spoilt fruits and beverages

In this study, seven yeast isolates were obtained altogether from both spoilt fruit and brukutu alcoholic drink using the spread plate method. Yeast strains were isolated from burukutu alcoholic drink, spoilt pineapple fruit and spoilt watermelon fruit, confirmed using API Test kit and subjected to flocculation, ethanol tolerance, hydrogen sulphide, temperature tolerance test and stress tolerance test to determine their fermentative potentials. In all ۷ species Candida sphaerica, Pichiaspp, Candida guilliermondii, Candidafamata Candida pelliculosa, Cryptococcus humicola and Kloeckeraapiculata were isolated. Candida sphaerica, Candida famata and Kloeckeraapiculata displayed the highest flocculation ability while only Candida famata and Candida pelliculosa survived ۱۵% ethanol concentration. Hydrogen sulphide test showed that only Candidafamata and Candida pelliculosa can survive the presence of hydrogen sulphide. All yeast isolated grew very well at ۲۵°C except Pichia species while only Candida pelliculosa grew at ۴۵°C. All the seven yeast isolated survived the first and second stage of stress while only Candida pelliculosa survived the last stage.

کلیدواژه ها:

Yeast ، Flocculation ، Ethanol tolerance ، Hydrogen sulphide ، Candida