Hydrocarbon Utilizing and Metal Tolerant Bacteria Simultaneously Degrade Hydrocarbons and Detoxify Metals in Petroleum Contaminated Soil

Abstract

Petroleum contamination to our biosphere particularly soil and water is due to release of petroleum products from petrochemical industries and is now a day’s biggest problem to the mankind. Present work was conducted to assess capability of hydrocarbon-utilizing and metal tolerant bacteria to degrade hydrocarbons and remediate metals in the soil contaminated with petroleum with the aim to form super bio-inoculants to restore soil to its original state. In order to achieve above goal, petroleum contaminated soil was observed for hydrocarbons using GC-MS, a total of 25 hydrocarbons were found in petroleum polluted soil with hydrocarbon concentration of 3738 mg/kg. Petroleum polluted soil was also observed for total bacterial population which was observed as 2.10 × 10⁶ CFU/g of soil. Strains YSA-7 and YSA-8 showed highest potential for hydrocarbon-utilization with an absorbance of 0.681 and 0.614 respectively. Strains were also highly tolerant to Cu and Zn with tolerance of 600 µg/ml (Cu) and 1500 µg/ml (Zn) by strain YSA-7 and 700 µg/ml (Cu) and 1800 (Zn) µg/ml by strain YSA-8. Strains YSA-7 and YSA-8 were identified by 16 SrRNA as Lysinibacillus fusiformis and Stenotrophomonas maltophilia, respectively. After 20 days of incubation, Lysinibacillus fusiformis strain YSA-7 and Stenotrophomonas maltophilia YSA8 degraded all twenty-five (25) compounds but there was complete degradation of 13 compounds by strain YSA-7 and 17 compounds by strain YSA-8 using GC-MS. Both strains (YSA-7 and YSA8) were significant and efficient for removing Cu and Zn using mechanism of biosorption at different pH, metal concentrations and time of incubation. Remediation of hydrocarbons and metals under in vitro conditions suggests that the inoculation of such bacteria to petroleum contaminated soil possessing mixture of contaminants such as hydrocarbons and metals can remove such pollutants from contaminated environment and can restore such habitat to its original state.

Keywords:

• Lysinibacillus fusiformis
• Stenotrophomonas maltophilia
• hydrocarbon utilization
• hydrocarbon degradation
• metal remediation

Acknowledgment

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Disclosure statement

No potential conflict of interest was reported by the author(s).