Leading edges in bioremediation technologies for removal of petroleum hydrocarbons

There is a worldwide concern regarding soil pollution caused by contamination of petroleum hydrocarbon, released during oil processing or production. Once a spill occurs, it disturbs the marine and freshwater ecosystem and greatly threatens human health. It usually requires complex technologies to remove it from soil. Petroleum hydrocarbons contain a range of chemicals which are extremely toxic and carcinogenic in nature. Although physical or chemical methods are widely employed for remediation, numerous studies revealed that bioremediation is a sustainable approach. Bioremediation is often preferred as clean and carbon-neutral solution. This review aims to provide series of sustainable solution for petroleum hydrocarbon degradation without exploiting the environment as well as opportunity to reuse treated media. Integrated and enhanced bioremediation technologies are more effective than natural degradation of petroleum hydrocarbons in terms of shorter time period and percent removal efficiency. It comprehensively illustrates bioremediation assisted with bacteria, fungi, and algae either by integrated technologies or by enhancing the process. Most recent application methods of petroleum hydrocarbon bioremediation (in situ and ex situ) are also reported. There is dire need to explore different cost-effective biotechnological resources for degradation of petroleum hydrocarbon by the screening of novel microbial strains or by the creation of genetically engineered bacteria to survive in harsh environment.