Biodegradation of cassava (Manihot esculentus) effluent using white rot fungus (Pleurotus ostreatus) and brown rot fungus (Gloeophyllum sepiarium)

Abstract

The utilization of cassava effluent as a sole carbon and energy source by white rot fungus (Pleurotus ostreatus) and brown rot fungus (Gloeophyllum sepiarium) was examined. The microorganisms were unable to utilize 100% unsterilized and sterilized effluent. The test organisms utilized 10% effluent in minimal salt medium (MSM) with P. ostreatus having a mean growth of 1.42 cm and G. sepiarium, 1.73 cm. When 2 g/l yeast was incorporated into 10% effluent in MSM, the mean growth increased to 1.97 cm for P. ostreatus and G. sepiarium, 1.89 cm. When the test organisms were incubated for 30 days at temperatures of 4 0C, 28 0C and 37 0C, P ostreatus had a growth of 0.96, 4.4 and 0.5 cm respectively and G. sepiarium, 0.63, 2.18 and 0.5 cm. When the pH of the medium was adjusted to 6, 8 and 10, P. ostreatus had mean growth of 2.77, 3.14 and 2.63 cm respectively and G. sepiarium, 1.74, 2.16 and 1.01 cm. The rate of biodegradation by these organisms was determined using C02 evolution method. P. ostreatus had a mean growth rate of 21.0 while G. sepiarium, 6.0. The results of this study show that these organisms can degrade cassava effluents, pH 8 appeared to be their optimum pH and 28 0C appeared to be their optimum temperature for biodegradation