Abstract

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Some toxic chemicals from petroleum products constitute environmental pollutants which are considered threats to ecological system. This study was performed to monitor the survival growth of some selected indigenous Pseudomonas strains isolated from petrochemical contaminated soil. Standard microbiological procedures and 16S rRNA technique were employed during isolation and identification of the strains. The physiochemical characteristics of the soil sample were conducted using standard laboratory procedure. Optimization of culture conditions were carried out under varying pH concentrations, moisture content, temperature and nutrients (N:P). The identified strains were P. aeruginosa PAER4 119, P. putida B6-2 and P. mendocina NK-01. The result of the soil physiochemical properties showed particle size distribution of 70.60 % for sand, 21.40 % for loam and 8.00 % for clay. The recorded pH value of 5.8, moisture content of 12.5 % and total petroleum hydrocarbons of 7.4 % were observed. The results of the optimization showed highest cell growth at temperature of 30 oC, pH value of 7, moisture content of 20 %, and nitrogen phosphorus ratio of 10:1. Maximum growth recorded during bioremediation by the strains were 2.90 x 1010 cfu/g for P. putida B6-2, 2.86 x 1010 cfu/g for P. aeruginosa PAER4 119 and 2.84 x 1010 cfu/g for P. mendocina NK-01. Cell growth increased with time. This study revealed the ability of Pseudomonas strains to grow and survive in the petrochemical contaminated soil. Hence, this study can be employed for successful bioremediation studies

Keywords: Petrochemicals, contaminated soil, Pseudomonas strains.