Morphological and biochemical characterization of saccharomyces species (yeasts) isolated from pineapple peels from 5 selected markets in Kampala

Abstract

Yeasts are widespread in terrestrial, aquatic and aerial environments. They have been isolated from natural substrates like leaves, flowers, sweet fruits, grains, fleshy fungi, exudates of trees, insects, dung and soil (Naiman, 2014). Preferred habitats are plant tissues, leaves and flowers, fruits, fermented products, soil and salt water (Naiman & Khan, 2014). They are members of Order Saccharomycetales. They occur with regularity in the bark of certain deciduous trees and intermittently in fermenting fruit and other high sugar environments such as nectar and sap fluxes. Many types of yeasts are used for making many foods: baker's yeast in bread production; brewer's yeast in beer fermentation; yeast in wine fermentation and for xylitol production. In Uganda, yeasts of economic importance are imported (Ngategize et al., 2001), none have been isolated from local wastes yet imported yeasts have been reported to exist in organic wastes (Ghosh, 2011). In this study, Saccharomyces yeasts were locally isolated from pineapple peel waste which is one of the highly abundant wastes generated in Kampala city. Five selected markets of Kampala region were considered for sample collection and yeast species were isolated using Potato Dextrose Agar. Kalerwe, Nakawa, Nakasero, Owino and Kasubi markets were the study sites because they are among the busiest markets with an abundance of pineapple wastes. They were then characterised based on their cultural and morphological characteristics. This study has revealed the presence of Saccharomyces yeasts in pineapple peel wastes, and five species were identified. This can lay a foundation for better isolation methods from even better local sources that would lead to better agricultural waste management through utilization.