ISOLATION AND IDENTIFICATION OF YEASTS FROM MAPRANG (Bouea macrophylla Griffith) IN CAN THO AND VINH LONG

Abstract

The study was performed to isolate and select yeast strains which show strong fermentation activity from maprang fruits. The following experiments were included: (i) isolation of yeasts from maprang fruits; (ii) determination of physiological and biochemical features of isolated yeast strains; (iii) fermetation test for selection of a yeast strain which has the best fermentation activity; (iv) molecular biological identification of the selected yeast strain. As a result, 17 yeast strains were isolated from 7 samples of maprang fruits growing in Vinh Long and Can Tho. Three genera of yeasts were identified on the basis of physiological and biochemical features including Saccharomyces (5 strains), Pichia (7 strains) and Hanseniaspora (5 strains). In the fermentation experiment with initial parameters including 24°Bx, pH of 4.5, yeast number of 10⁶ cell/mL, 30 ± 2℃ for 11 days, the strain named CT1.4 (Saccharomyces) gave highest ethanol level (12% v/v) and lowest final Brix (7°Bx). Molecular identification using Sanger sequencing method showed that CT1.4 belonged to Saccharomyces cerevisiae (99.91%).