Biodegradation Potentials of Mycoflora Isolated from Auto Mobile Workshop Soils on Flow Station Crude Oil Sludge

摘要

The biodegradation potentials of soil mycobiota isolated from six auto mobile workshops and a farmland in Benin City on flow station crude oil sludge was investigated. Serial dilution and pour plate methods were utilized in the isolation and enumeration of the fungal bioload of the soil samples. The heterotrophic fungal counts ranged from 0.2 -10 cfu/g to 3.6 -10 cfu/g. Twenty (20) fungal species were identified from the soil samples; Aspergillus flavus, Aspergillus terrus, Aspergillus fumigatus, Aspergillus versicolor, Emericella nidulans, Aspergillus tamarii, Aspergillus niger, Aspergillus sp., Moniliella sp., Pichia farinosa, Sporobolomyces sp., Candida sp., Rhodotorula sp., Curvularia sp., Mucor sp., Rhizopus stolonifer, Penicillium sp., Penicillium sp.2, Penicillium italicum and Penicillium chrysogenum. A. flavus and A. nidulans had the highest percentage prevalence (85.7%). Physicochemical analyses revealed that the soil samples were acidic (pH 5.81-6.40) and sandy (50.3%-64.80%). Colorimetric screening indicated that Aspergillus flavus, Aspergillus terrus, Aspergillus sp., Penicillium sp., consortium of yeasts and the filamentous fungal consortium were able to maximally utilize the sludge as the sole source of carbon and energy. The growth profile results obtained for A. flavus revealed a decrease in pH (7.2 - 4.8), an increase in turbidity and colony counts (12 FAU - 229 FAU) (1.8 - 10 cfu/ml - 3.6 - 10 cfu/ml) during the 20 day incubation period. Amongst the growth profile cultures, Aspergillus flavus caused the highest percentage reduction in the residual TPH (DRO) content of the inoculated sludge (84%). Soils within the vicinities of auto mechanic workshops are viable sources of hydrocarbonclastic fungi.