Bioremediation of engine-oil polluted soil by Pleurotus tuber-regium Singer, a Nigerian white-rot fungus

White-rot fungi have been used in various parts of the world for bioremediation of polluted sites. Pleurotus tuber-regium was noted to have the ability to increase nutrient contents in soils polluted with1 - 40% engine-oil concentration after six months of incubation. P. tuber-regium increased organic matter, carbon and available potassium 5.19%, 2.99% and 0.97 meq/100 g respectively compared to4.41%, 2.56% carbon and 0.66 meq/100 g, respectively in the control. However, higher values of 0.32% nitrogen, 11.42 ppm phosphorus and pH 6.94 were obtained in the control compared to 0.16% nitrogen,9.32 ppm phosphorus and pH 5.93 in soils incubated with the fungus. The fungus brought about an increase in copper content in engine oil polluted soils at 10% concentration followed by a decrease at 20 and 40% concentrations. Bioaccumulation of zinc and nickel was recorded at 20% engine-oil concentrations

Bioremediation of soil contaminated by spent diesel oil using Pleurotus pulmonarius Fries (Quelet) and its effects on the growth of Corchorus olitorius (L)

Objectives: To investigate the potential of Pleurotus pulmonarius in the bioremediation of soil contaminated with spent diesel oil at 5, 10 and 15% (v/w) level of contamination over a period of one and two months of incubation.Methodology and results: A pure culture of P. pulmonarius was obtained from the Plant physiology unit of the Department of Botany, University of Ibadan Two sets of control were used. In the first set of control treatments, no contaminant ( spent diesel oil was added to the soils while in the second set, different levels of oil were added to all soils but no inoculation with the fungus). Inoculation was done by adding 10 g of vigorously growing spawn of P. pulmonarius. The soil was contaminated with spent diesel oil to achieve 5 %, 10 % and 15 % (w/v).. The results showed a significant increase (at p3 0.05) in the nutrient contents of the soil samples at all level of contamination compared to the uncontaminated but there was no significant difference in the pH after two months of incubation with P. pulmonarius. The organic carbon increased from 2.176 to 6.960 at 0% and from 7.126 to 8.010 at 15 % level of contaminations. Organic matter increased from 3.765 to 12.03 at 0% level of contamination and from 12.32 to 13.84 at 15%. Phosphorus increased from 15.807 to 18.940 at 0% and 16.017 to 20.627 at 5% level of contaminations while Potassium increased from 0.660 to 0.783 at 0% and 0.540 to 0.837 at 10% level of contamination. The Total Petroleum Hydrocarbon (TPH) degradation (% loss) was 84.41% at 5%, 64.87% at 10% and 44.27% at 15% level of contamination. . A significant (p 30.05) reduction in concentration of the heavy metals Cu and Zn after two month of incubation with P. pulmonarius suggested bioaccumulation. The Copper content reduced from 0.033 to 0.014mg/kg at 0% oil contamination and from 0.027 to 0.021mg/kg at 15% oil contamination while Zinc reduced from 0.076 to 0.059mg/kg at 0% oil, and from 0.057 to 0.056mg/kg at 15% oil contamination. There was an improvement in the growth of Corchorus olitorius in remediated soil at all level of contamination compared to the control. Plant growth in the remediated soil was 11.18 cm high after the sixth week while the control plant was 4.23 cm at 5% level contamination.Conclusion and application: The fungus P.pulmonarius has been found from this study to be a potential white rot fungus that can bioremediate soil contaminated with diesel oil and that the remediated soil was able to support the growth of the test plant at all level of contaminations. The biotechnology is a cost energy input that can also fetch the farmer some income.Key words: Bioremediation, Spent diesel oil, Degradation, P. pulmonarius, Soil nutrient conten

Biodegradation of polycyclic aromatic hydrocarbons (PAHs) in spent and fresh cutting fluids contaminated soils by Pleurotus pulmonarius (Fries). Quelet and Pleurotus ostreatus (Jacq.) Fr. P. Kumm

The potential of Pleurotus pulmonarius and Pleurotus ostreatus on the degradation of PAHs in spent and fresh cutting fluids (SCF and FCF) contaminated soils was investigated. Different weights of soil samples were contaminated with varying composition (10, 20 or 30%) of spent and fresh cutting fluids separately then inoculated each sample with P. pulmonarius and P. ostreatus separately and incubated at 28 ± 2°C for two months. The samples were analyzed in triplicates for 16 priority polycyclic aromatic hydrocarbons (PAHs) by gas chromatography after extracting with hexane and dichloromethane (3:1). The initial PAHs in the cutting fluids were mainly composed of 2 to 6 fused benzene rings. Significant reductions in PAHs concentrations for SCF and FCF were observed after two months of incubation. The percentage total PAHs remaining in FCF soil ranged from 71.7 to 73.6% when inoculated with P. pulmonarius and 0.93 to 31.0% when inoculated with P. ostreatus. Similarly, the percentage total PAHs remaining in SCF soil ranged from 42.6 to 72.6% when inoculated with P. pulmonarius and 54.9 to 62.2% when inoculated with P. ostreatus. Overall range of PAHs degradation by P. pulmonarius inoculated on FCF contaminated soil was 17.3 to 27.3%, while for P. ostreatus inoculated soil was 69.0 to 99.07% at different contamination levels. In contrast, overall PAHs degradation for P. pulmonarius and P. ostreatus inoculated on SCF ranged from 27.4 to 57.4% and from 37.8 to 45.2%, respectively. Thus, P. ostreatus is found more effective as a biodegradation agent for PAHs in contaminated soils when compared with P. pulmonarius. Key words: Biodegradation, polycyclic aromatic hydrocarbons (PAHs), cutting fluids, Pleurotus ostreatus, Pleurotus pulmonarius