The increase of anthropogenic activities and growth of technology in Antarctica is fuelled by the high demand for petroleum hydrocarbons needed for daily activities. Oil and fuel spills that occur during explorations have caused hydrocarbon pollution in this region, prompting concern for the environment by polar communities and the larger world community. Crude oil and petroleum hydrocarbon products contain a wide variety of lethal components with high toxicity and low biodegradability. Hydrocarbon persistence in the Antarctic environment only worsens the issues stemming from environmental pollution as they can be long-term. Numerous efforts to lower the contamination level caused by these pollutants have been conducted mainly in bioremediation, an economical and degrading-wise method. Bioremediation mainly functions on conversion of complex toxic compounds to simpler organic compounds due to the consumption of hydrocarbons by microorganisms as their energy source. This review presents a summary of the collective understanding on bioremediation of petroleum hydrocarbons by microorganisms indigenous to the Antarctic region from past decades to current knowledge.
Petroleum hydrocarbons remain as the major contaminants that could be found across the world.
Remediation approach through the utilisation of microbes as the bioremediation means widely
recognised due to their outstanding values. As a result, scientific reports on the isolation and
identification of new hydrocarbon-degrading strains were on the rise. Colourimetric-based assays
are one of the fastest methods to identify the capability of hydrocarbon-degrading strains in both
qualitative and quantitative assessment. In this study, the hydrocarbon-degrading potential of
nine bacterial isolates was observed via 2,6-dichlorophenolindophenol (DCPIP) test. Two potent
diesel-utilising isolates show a distinctive tendency to utilise aromatic (ADL15) and aliphatic
(ADL36) hydrocarbons. Both isolates prove to be a good candidate for bioremediation of wide
range of petroleum hydrocarbon components.
Carbamates are poisonous pesticides which have been used widely in agriculture production for decades. Unlike other pesticides such as organophosphate, carbamate pesticides are not persistent in the environment however, their degradation is crucial due to their toxicity to living system. The World Health Organization, categorized carbamate pesticide as toxic, hazardous and restricted for use. Example of carbamates pesticides include Carbaryl, Aldicarb, Methomyl, Carbofuran, and Propoxur. They are extensively used to control many insect and pests of crops. Presently, there is significant awareness regarding the negative effects of pesticides due to their ability to pollute soil and water bodies. Most pesticides are readily degraded or metabolized by microbes. Carbamate pesticide degradation by microorganisms relies not only on the availability of microbes with suitable biodegradative enzymes, but also on the various ecological factors. This reviewarticle outlines the present development in biodegradation of carbamate pesticides, their toxicity and enzymatic degradation as well as their degradative pathways.
Recently, the contamination of heavy metals towards the environment especially in aquatic system has drastically increased. Heavy metals are able to transform into persistent metallic compound in which it can be accumulated within the organisms’ body system, disrupting the food chain and eventually threatened the human life. The occurrence of heavy metals spillage in the rivers and lakes are due to the careless disposal of excess heavy metals used for human activities. The accumulation of heavy metals in water system will affect all aquatic organisms especially fish. The toxicity of copper in fish can be determined by several changes in the fish under treatment with heavy metals sub-lethal concentration, LC50 within 96-hours period of acute exposure. Therefore, fish can be considered as a high potential biomarker for monitoring heavy metals pollution in aquatic system. Several selective organs are highly sensitive to the xenobiotic pollution and express changes to the exposure. One of the most potential biomarker is the biochemical biomarker of cholinesterase (ChE) inhibition by heavy metals in fish has been well studied in pollution monitoring recently. Thus, this paper gives an overview of the manipulation of fish as a biomarker of heavy metals through enzymatic reaction which have proven to be very useful in the environmental pollution monitoring.