Utilization of Food Crop Wastes for the Formulation of Laboratory Media Used for Cultivating Soil Fungi

Abstract

A major problem experienced by both developed and developing countries is the management of wastes. Thus, there is a growing interest regarding the conversion of organic wastes generated by the food processing sector and through other human endeavors into useful forms. An investigation was carried out to test the suitability of food crop wastes (yam, sweet potato, carrot and Irish potato peels) for the formulation of media for cultivating soil fungi. Four formulated media which included Yam Peel Dextrose agar (YPDA), Sweet Potato Peel Dextrose Agar (SPPDA), Carrot Peel Dextrose Agar (CPDA) and Irish Potato Peel Dextrose Agar (IPPDA) were used to determine the growth of four test fungi isolated from the soil. Mean radial growths (MRGs) of the isolates on the formulated waste media were determined and compared with that of SDA which served as the control. The test organisms were aseptically inoculated unto the four different formulated media and the control medium in triplicates. The cultures were incubated for a period of six days and the radial growth of each of the fungi was measured thereafter. Growth rates on the test media were also calculated for each fungus. The fungal isolates from this study were Aspergillus niger, Geotrichum candidum, Aspergillus flavus and Saccharomyces cerevisiae. All the formulated media supported the growth of the test fungi at various degrees with Sweet Potato Peel Dextrose Agar (SPPDA) having the highest MRG of 8.10 cm, 8.10 cm and 7.40 cm for A. niger, G. candidum and S. cerevisiae respectively. The MRGs of these three fungi on SPPDA were found to be higher than their MRGs on all the other media including the control medium (SDA), while the control (SDA) yielded the highest MRG for A. flavus. Yam Peel Dextrose Agar (YPDA) yielded the lowest MRG values for all the test fungi. Seventy-five percent of the fungi demonstrated higher growth rates on SPPDA. There is promise for the use of SPPDA for the cultivation of the test soil fungi.