Physiochemical Properties and Biodegradation Potentials of Soil Microbes Isolated from Mechanic Workshops in Benin Metropolis

Abstract

The release of used engine oil into the environment is gradually becoming a challenge to our environment.
This research was carried out to determine the physiochemical properties and biodegradation potentials of some
soil microbes isolated from mechanic workshops in Benin metropolis. The physiochemical properties of the
soil samples were investigated according to the methods of Association of Official Analytical Chemists. The
microbial analysis was carried out according to standard microbiological and biochemical methods. Results
revealed bacterial count ranged from 1.6×10⁴ – 3.8×10⁴ cfu/g, Hydrocarbon utilizing bacterial counts ranging
from 0.4×10⁴ – 1.0×10⁴ cfu/g. Fungal counts ranging from 0.1×10⁴ – 0.7×10⁴ cfu/g. The bacteria isolated
were Pseudomonas aeruginosa, Micrococcus luteus, Bacillus subtilis, Acinetobacter spp., Corynebacterium spp. and
Klebsiella spp. The fungi isolates identified were Trichoderma spp., Penicillium spp., Mucor spp., Aspergillus
niger and Fusarium spp. The screening test revealed Bacillus subtilis, Pseudomonas aeruginosa, Trichoderma
spp. and Aspergillus niger to have biodegradative potentials. Shake flask experiment revealed increased in the
turbidity of the mineral salt medium amended with engine oil. The consortium of bacterial and fungal showed
better degradation potentials especially with the gradual increase turbidity and reduction in pH. The results
suggest that the consortium of the isolates could be used in remediating contaminated soils.