Microbial degradation of hydrocarbons in the environment

Abstract

The ecology of hydrocarbon degradation by microbial populations in the natural environment is reviewed, emphasizing the physical, chemical, and biological factors that contribute to the biodegradation of petroleum and individual hydrocarbons. Rates of biodegradation depend greatly on the composition, state, and concentration of the oil or hydrocarbons, with dispersion and emulsification enhancing rates in aquatic systems and absorption by soil particulates being the key feature of terrestrial ecosystems. Temperature and oxygen and nutrient concentrations are important variables in both types of environments. Salinity and pressure may also affect biodegradation rates in some aquatic environments, and moisture and pH may limit biodegradation in soils. Hydrocarbons are degraded primarily by bacteria and fungi. Adaptation by prior exposure of microbial communities to hydrocarbons increases hydrocarbon degradation rates. Adaptation is brought about by selective enrichment of hydrocarbon-utilizing microorganisms and amplification of the pool of hydrocarbon-catabolizing genes. The latter phenomenon can now be monitored through the use of DNA probes. Increases in plasmid frequency may also be associated with genetic adaptation. Seeding to accelerate rates of biodegradation has been shown to be effective in some cases, particularly when used under controlled conditions, such as in fermentors or chemostats.

Effectiveness of a bio-catalytic agent used in the bioremediation of crude oil-polluted seawater

“…The increase in total demand for energy and water has led to the implementation of water-intensive forms of power generation and energy-intensive platforms of water production, primarily driven by population growth. Consequently, this excessive energy consumption has triggered the frequent exploitation of hydrocarbon reserves without considering the environmental impacts on terrestrial, aquatic and aerial ecosystems ( Leahy and Colwell, 1990 ). The limited biodegradation capacity of petroleum-derived hydrocarbons and their low reactivity represent a significant threat to the environment, owing to the high level of toxicity and inhibition to plant and animal growth and their mutagenic and carcinogenic characteristics ( United Nations Educational Scientific and Cultural Organization, 2019 ).…”

In situmicrocosms deployed at the coast of British Columbia (Canada) to study dilbit weathering and associated microbial communities under marine conditions

“…Like other types of crude oil, dilbit consists of saturates, aromatic hydrocarbons, resins and asphaltenes (King 2019 ). Resins and asphaltenes are considered to be highly resistant to biodegradation (Leahy and Colwell 1990 ) and are assumed to not induce toxicity in aquatic organisms (Khan 2008 ). In contrast, saturates, such as n-alkanes, and aromatics have been shown to be more readily biodegradable (Leahy and Colwell 1990 ), and are, in the case of polycyclic aromatic hydrocarbons (PAHs), also of ecotoxicological importance (Hylland 2006 ).…”

Statistical Optimisation of Diesel Biodegradation at Low Temperatures by an Antarctic Marine Bacterial Consortium Isolated from Non-Contaminated Seawater

“…Low bacterial growth, such as seen at the higher temperatures used here, can be associated with the denaturation of key cellular components, while low temperatures may restrict bacterial growth through the loss of membrane function [78]. Within the functional temperature range of a given species, microbial metabolism increases with temperature [79], while diesel uptake or assimilation is also affected by temperature [80]. In the presence of diesel, temperature can influence the active bacterial community structure because only some species are responsible for the biodegradation of specific hydrocarbons [81,82].…”