Yeasts from Nigerian Fruits and their Growth on Formulated Media

An investigation was carried out on the distribution of yeast species amongst some ripe Nigerian fruits of economic importance with a view to selecting good strains of industrial yeasts for Nigerian bakeries, breweries and wineries. The fruits examined included Anarcadium occidentale (Cashew-Pulp), Annona muricata (Sour-sop), Carica papaya (Paw-Paw), Citrus sinensis (Orange), Irvingia smithii (African apple), Mangifera indica (Mango) Musa sapientum (Banana) and Psidium guajava (Guava). Six yeast isolation methods were employed. The experimental fruits were analyzed for their percentage sugar contents, percentage moisture contents and the range of pH of their juices. Experiments were also carried out on the abilities of the various species of yeast isolated to grow on media formulated out of the fruit juices. This included the ability of these species of yeast to utilize the fruit juices in such media as the sole sources of Carbon, Nitrogen and Vitamins. Thirty four species of yeast belonging to 7 genera were isolated from the fruits. The implications of these results with regards to the development of alcoholic beverages and bakery industries in Nigeria have been discussed.