Current Status of the Degradation of Aliphatic and Aromatic Petroleum Hydrocarbons by Thermophilic Microbes and Future Perspectives

Abstract

Contamination of the environment by petroleum products is a growing concern worldwide, and strategies to remove these contaminants have been evaluated. One of these strategies is biodegradation, which consists of the use of microorganisms. Biodegradation is significantly improved by increasing the temperature of the medium, thus, the use of thermophiles, microbes that thrive in high-temperature environments, will render this process more efficient. For instance, various thermophilic enzymes have been used in industrial biotechnology because of their unique catalytic properties. Biodegradation has been extensively studied in the context of mesophilic microbes, and the mechanisms of biodegradation of aliphatic and aromatic petroleum hydrocarbons have been elucidated. However, in comparison, little work has been carried out on the biodegradation of petroleum hydrocarbons by thermophiles. In this paper, a detailed review of the degradation of petroleum hydrocarbons (both aliphatic and aromatic) by thermophiles was carried out. This work has identified the characteristics of thermophiles, and unraveled specific catabolic pathways of petroleum products that are only found with thermophiles. Gaps that limit our understanding of the activity of these microbes have also been highlighted, and, finally, different strategies that can be used to improve the efficiency of degradation of petroleum hydrocarbons by thermophiles were proposed.

Contribution of Yeast Extract, Activated Carbon, and an Electrostatic Field to Interspecies Electron Transfer for the Bioelectrochemical Conversion of Coal to Methane

“…Methane production in subsurface coal beds is generally attempted under thermophilic conditions. This suggests that the aromatic and aliphatic compounds might be broken down more efficiently by thermophilic microorganisms [61]. Coal conversion to methane under thermophilic conditions is a further research topic that must be explored in order to significantly improve the production of methane from coal.…”

Current Status of and Future Perspectives in Bacterial Degradation of Benzo[a]pyrene

“…They also have an anthropogenic source, as the result of the incomplete burning of coal, wood, oil, tobacco, and meat cooking at high temperature [ 1 , 2 ]. PAHs are classified into low-molecular-weight PAHs (LMW-PAHs), consisting of two or three fused rings such as naphthalene, phenanthrene, anthracene, and fluorene; and high-molecular-weight PAHs (HMW-PAHs), consisting of four or more rings such as fluoranthene, pyrene, benzo[a]anthracene, and benzo[a]pyrene (BaP) [ 1 , 2 , 3 ].…”

Bioremediation of groundwater contaminated with petroleum hydrocarbons applied at a site in Belgrade (Serbia)

“…In most aromatic hydrocarbons, the diol group is formed in the first stage of degradation, when dioxygenases incorporate two atoms of oxygen into the aromatic hydrocarbon molecules. 4 New formed cis-cis diol, catechol, 10,11 is further transformed to a carboxylic acid and Acetyl-CoA ( Fig. 2).…”

“…More aromatic groups result in higher resistance to degradation and vice versa. 11 In the absence of oxygen, various mechanisms such as the addition of fumarate, carboxylation, hydroxylation and methylation can initially activate hydrocarbons. 13,14 Addition of fumarate is the most common mechanism used by O n L i n e F i r s t different anaerobic microorganisms to activate alkanes (linear and cyclic) or alkyl-branched aromatic compounds (alkylbenzenes, methylnaphthalenes, etc.).…”