Bio-stimulation of microbial degradation of crude oil polluted soil using cow dung and plantain peels

Abstract

Biostimulation of microbial degradation of crude oil-polluted soil using cow-dung and plantain peels was investigated. Top soil (0 to 20 cm depth) was randomly collected from four points using a Dutch auger, then bulked to form composite soil sample. Eight kilogram (8 kg) of each composite soil was weighed and transferred into forty five (45) labeled plastic buckets with drainage holes at the base. The soils contained in the buckets were polluted with 200 ml of crude oil each except the pristine control and were mixed thoroughly and allowed for 14 days. Soil samples were collected for microbial analysis after three weeks of soil treatment. The result showed that the combined treatment (cow dung + plantain peels) yielded the highest crude oil-utilizing bacteria (CUB) counts of 11.73 × 10⁴ CFUg^-1 at 750 g. Also the combined treatment (CD + PP) produced the highest crude-oil utilizing fungi (CUF) counts of 7.20 × 10⁴ CFUg^-1 at 750 g. Twelve bacterial genus: Bacillus sp., Staphylococcus aureus, Actinomyces sp., Pseudomonas aeruginosa, Micrococcus sp., Achromobacter sp., Flavobacterium sp., Escherichia coli, Campylobacter sp., Serriatia marcescon, Enterobacter sp., Corynebacterium sp.; and eight fungal species: Fusarium sp., Chrysosporium sp., Aspergillus sp., Penicillum sp., Yeast sp., Rhizopus sp., Trichoderma sp. and Mucor indicus were isolated. The result of the total hydrocarbon content (THC) analysis showed that the higher the concentration of the agro-wastes, the more the reduction of the hydrocarbon content. It therefore suggests that the combined treatment of cow-dung and plantain peels (CD + PP) should be considered as one of the best options for bioremediation of crude oil polluted soil.

Keywords: Biostimulation, microbial degradation, crude oil, cow dung, plantain peel.