HYDROCARBON DEGRADATION POTENTIAL OF ASPERGILLUS NIGER AND MICROCOCCUS SPP. INDIVIDUALLY AND IN CONSORTIUM

Abstract

Oil pollution is a pervasive and significant global problem, with hexadecane (C₁₆H₃₄), decane (C₁₀H₂₂), and heptane (C₇H₁₆) as major components of petroleum-based fuels such as gasoline, kerosene, and diesel. Eight Fungal isolates identified as engine oil degraders were isolated across five mechanic workshops in Ilorin, Nigeria and identified using cultural and morphological characteristics. They include: Aspergillus niger, Aspergillus brasiliensis, Trichophyton rubrum, Aspergillus tabacinus, Penicillium chrysogenum, Trichophyton terrestre, Rhizopus stolonifer and Fusarium oxysporium. Trichophyton rubrum, which is a leading cause of dermatophytoses, had the highest prevalence (76%) across the five sites. Aspergillus niger exhibited the highest degradation ability, degrading hexadecane the most (from 0.207 to 0.424 OD600) and heptane the least (from 0.27 to 0.19 OD600) over 20 days. Micrococcus spp. previously isolated from air and Aspergillus niger isolated from engine oil-polluted mechanic workshop were utilized for degradation for 5 days; In consortium, Aspergillus niger and Micrococcus spp. hydrocarbon utilization rates ranged from 0.106 to 0.202 for decane, from 0.106 to 0.193 for heptane, and from 0.207 to 0.467 for hexadecane.  Micrococcus spp., when used singly, had a higher degradation rate for the heptane-plus-petrol mixture (0.011 to 0.061) than Aspergillus niger in consortium, with a degradation rate ranging from 0.115 to 0.06. Optical density and pH measurements were taken to determine degradation rates. These findings show that Aspergillus niger and Micrococcus spp. can be used to enhance the biodegradation of oil-polluted soil, but might work much better separately than in a consortium.