Bioremediation Potentials and Emulsification Activity of Indigenous Bacteria Isolated from Crude Oil Polluted Soil in Ohaji-Egbema, Nigeria

Abstract

Sweet potatoes are tuber crops consumed in different parts of the world. Its use is however limited by post-harvest spoilage by microorganisms. This study was carried out to isolate, identify, and prevent the microorganisms responsible for the post-harvest spoilage of sweet potato. Five replicate samples of decaying sweet potatoes were obtained randomly at different time intervals from the local markets in Ile-Ife. They were homogenized and serially diluted to ‘thin-out’ the microbial population. Nutrient agar and potato dextrose agar were used for the isolation and identification of bacteria and fungi respectively. The bacterial population were estimated after 24 hours of incubation while the fungi were observed after 5 days of incubation. The organisms were identified using standard morphological and biochemical tests. The total aerobic bacterial count of the samples ranges from 1.81 x 105cfu/g to 1.28 x 107cfu/g while the fungi load ranges from 1.80 x 107sfu/g to 2.90 x 107sfu/g. The genera of the bacteria isolated and their percentage of occurrence include; Staphylococcus (40%), Bacillus (30%), Pseudomonas (20%), Micrococcus (10%), while the genera of the fungi isolated and their percentage of occurrence include; Aspergillus (40%), Mucor (30%), Fusarium (10%), Penicillium (10%), and Geotrichum (10%). The microorganisms gained entry into the sweet potato majorly through openings on the tubers caused by several injuries and are able to proliferate because of the temperature and the humidity of storage condition of the tuber. These microorganisms then breakdown the starch present in the tuber and therefore leads to spoilage of sweet potato.