Bioremediation of Crude Oil Polluted Soil Using Biofertilizer from Nitrogen-fixing and Phosphate-solubilizing Bacteria

摘要

This study examined bioremediation of crude oil polluted soil (PS) stimulated with nitrogen-fixing bacteria (NFB) and phosphate-solubilizing bacteria (PSB). Five set-ups designated as A (500 g PS + 50 g NFB); B (500 g PS + 50 g PSB); C (500 g PS + 50 g NFB+PSB); D (500 g PS + 50 g NPK); and E (500 g PS only: control) were designed. Total petroleum hydrocarbons (TPHs) were monitored for 4 weeks. Toxicity of the biofertilizer on maize plant was determined. The combination of the biofertilizers with normal soil for the ecotoxicity testing was in the following ratios: 100:0, 75:25, 50:50, 25:75, and 0:100. The NFB were classified as Azotobacter sp. and Rhizobium sp. while the PSB identifies as Pseudomonas and Bacillus using their 16S rRNA gene sequences and deposited in GenBank under the accession numbers MN134485.1-MN134488.1. After 28 days study, TPH reductions were 97.8%, 97.5%, 94.3%, 92.1%, and 34.6% in NFB, NFB+PSB, PSB, NPK treatments, and control. There was significant difference (P<0.05) between the set-ups when compared to the control. For toxicity testing, the 25:75 concentration in all treatment set-ups best supported plant growth. It was concluded that biofertilizer is effective in remediating oil contaminated soil and in improving soil fertility.