Screening of Yeast Cells for the Production of Wine from Banana and Pineapple Substrates

Abstract

Wine, an alcoholic beverage is usually produced from juice of variety of fruits by the fermentative action of microorganisms particularly by yeasts. Several substrates such as pineapple, banana, watermelon, pawpaw and other fruits have been used to produce wine using Saccharomyces species. This study was undertaken using non- Saccharomyces to produce table wine with pineapple and banana fruits as substrates. Standard microbiological procedures were employed for yeasts cell isolation, sugar (sucrose) fermentation test, pH, ethanol, sucrose and glucose tolerance test were carried out respectively. Alcohol production by the yeasts was screened and the isolates were identified by genomic techniques. Twenty-two (22) yeasts isolated from palm wine (YW), banana (YB) and pineapple (YP) were screened for their ability to ferment sugar and fourteen (14) of the yeast isolates were positive while eight (8) were negative. The fourteen (14) isolates were further screened for their ability to tolerate pH, ethanol, sucrose and glucose. Tolerance tests for these fourteen (14) yeast isolates recorded values between a range of 3.0-5.0, 0-10% v/v, 5-20% w/v and 5-25% w/v for pH, ethanol, sucrose and glucose concentrations respectively. Statistically, there was a significant difference in the interaction effect for pH, ethanol, sucrose and glucose tolerance (OD600 nm) for yeast isolates at p value ≤ 0.0001. Five (5) yeast isolates had high tolerance ability to pH, ethanol, sucrose and glucose and were further screened for their ability to produce alcohol. The five (5) yeast isolates were identified as Meyerozyma guilliermondii strain 1621, Pichia guilliermondii strain PX-PAT, Meyerozyma caribbica strain Kw 1S7Y2, Meyerozyma caribbica strain Y-27400, Kodamaea ohmeri strain ww1-1 and they produced alcohol content of 7.6%, 6.5%, 2.9%, 2.5% and 0.3% respectively. Meyerozyma guilliermondii strain 1621 and Pichia guilliermondii strain PX-PAT 18 S isolated from palm wine exhibited good characteristics and produced high quantity of alcohol and are suitable for alcohol fermentation of substrates for wine production.