Effects of lead on petrol degradation efficiency of bacteria isolated from soils in zhuhai, guangdong, china

Abstract

Soil pollution, particularly of petroleum hydrocarbons and lead contamination, has become increasingly concerned due to rapid urbanization and industrial development. Bioremediation of petroleum hydrocarbon pollution using microorganisms is a promising solution due to the absence of secondary contamination. In this study, two bacterial isolates (B-7 and B-10), with distinctive colony characteristics, were screened from petroleum contaminated soil collected in Zhuhai, Guangdong Province, China. Using 16S rRNA sequencing technique and biochemical analyses, B-7 and B-10 were identified to be closely related to Achromobacter denitrificans, and Mycolicibacterium phocaicum N4, respectively. Petrol degrading rates of the two isolates were determined by UV-visible spectrophotometer in this study. With consideration of recovery rate and background evaporation rate, in the absence of lead, in a five-day interval study, the petrol degradation rate of B-7 and B-10 was observed at approximately 2.4g petrol/L for both isolates. Co-contamination with lead at 1, 5, 10 and 20ppm significantly inhibited petrol degrading potential of both isolates, with B-10 demonstrated significantly higher lead tolerance. Future studies are needed to evaluate the effects of other abiotic factors, such as pH, temperature, nutrient contents and concomitant exposure to other pollutants and biotic factors, such as microbial community, on the petroleum hydrocarbons degrading efficiency of these isolates.