Bioremediation of Crude Oil-Polluted Soil with a Consortium of Pseudomonas Aeruginosa and Soybean Hull

Bioremediation, Crude Oil, Pseudomonas aeruginosa, Soybean Hull, Biostimulation, Bioaugmentation, Soil Health, Environmental Restoration, Toxic Metals

Abstract

This study investigates the bioremediation of crude oil-contaminated soil using Pseudomonas aeruginosa isolates with soybean hull as a biostimulant. The experimental setup included biostimulation, bioaugmentation, and hybrid approaches with bacterial strains KUD-1, KUD-2, KUD-3, and KUD-4. Molecular identification confirmed these strains as Pseudomonas aeruginosa. Over a five-week incubation period, key physicochemical properties, such as pH,electrical conductivity, moisture content, and levels of essential nutrients, were monitored. The results demonstrated significant reductions in toxic metals, with chromium (Cr+6) decreasing from 52.1 mg/kg to 13 mg/kg, iron (Fe) from 16,350 mg/kg to 560 mg/kg, and residual crude oil content from 0.51 g/10g to 0.11 g/10g. Improvements in soil fertility markers were also observed,with total nitrogen increasing from 126.6 mg/kg to 300 mg/kg, and total organic carbon rising from 0.761% to 6.55%. The pH of the soil increased from 6.28 to 7.78. This study underscores the effectiveness of biostimulation and bioaugmentation in enhancing the bioremediation process and restoring soil health, offering a sustainable solution for mitigating crude oil pollution.