The oil spills are the major controversial issue in the marine environment because natural degradation of oils or hydrocarbons is a very slow process, so it leads to several environmental related issues. There are many types of bacteria which are capable of degrading petroleum hydrocarbons. So many researchers have been isolated and characterized it from the contaminated site, still, a majority of hydrocarbon-degrading bacteria, including anaerobes, could remain unexplored, as a huge portion of bacteria residing marine environments is uncultivable. But by using advanced molecular technologies like culture-independent rRNA approaches such as 16S rRNA gene (rDNA) clone libraries, fluorescence in situ hybridization (FISH) analysis with rRNA-targeted oligonucleotide probes, and denaturing gradient gel electrophoresis (DGGE) of PCR-amplified rDNA these techniques have been introduced in microbial ecology it can resolve the problem in a greater extent. And also it may help to improve the structure of microbial communities/strains from oil spill pollutant marine environments. There are some native microbes which really helps to eradicate such pollutants it ensures the wide scope of microbial ecology.
Alcanivorax and Cycloclasticus of the g-Proteobacteria were recognised as key organisms with a chief role in the degradation of petroleum hydrocarbons. In that Alcanivorax is for alkane biodegradation, whereas Cycloclasticus degrades various aromatic hydrocarbons. Apart from them, there are other bacteria’s such as genera: Pseudomonas, Flavobacterium, Oleiphilus, Oleispira, Neptunomonas and vibrio it also helps in oil spill/petroleum biodegradation. Nowadays in situ bioremediation strategies are also approachable for a clear-out of marine oil spills pollutants. Alcanivorax and Cycloclasticus are oligotrophs and not adapted for growth in media (in vitro) containing a high concentration of organic carbon have gained credence. To cultivate those microbes they use low concentrated organic carbon marine water. This technique, referred to as ‘extinction culturing’, was used to isolate the oligotrophic aromatic hydrocarbon-degrading bacterium Cycloclasticus oligotrophium. Petroleum ingredients are classified: 1.saturates, 2.aromatics, 3.resins and 4.asphaltenes. Each of these fractions is highly complex compounds. Saturates are hydrocarbons containing no double bond and are further classified according to their chemical structures into alkanes (paraffins) and cycloalkanes (naphthenes). They are the major constituents of crude oil. Aromatic hydrocarbons have one or more aromatic rings with or without alkyl substitution(s). In contrast to the saturated and aromatic fractions, both the resin and asphaltene fractions contain non-hydrocarbon polar compounds. When petroleum gets leaked into the sea, it spreads all over the surface of the water. It is subjected to many modifications and the composition of the petroleum changes with time. This process is termed as weathering and it is mainly due to evaporation of the low molecular weight fractions, dissolution of the water-soluble components etc. The rapid development of molecular methods which specifically helped for detecting biodegrading microbial populations from natural environment without doing in vitro cultivation. However, the maintenance of specific metabolic activities of certain biodegrading species is not yet an easy task. Undeniably, many recent efforts to understand environmental microbiology have been aimed at linking the identity with the biogeochemical activity of microorganisms in a natural environment. The studies clearly pointed out that the abundance and localization of each taxonomic group of bacteria in situ, but also their activities in situ. Novel approaches in biology such as microbial biotechnology, environmental engineering helped to overcome the intensity of oil spill pollutant in marine.
REFERENCE:
https://www.sciencedirect.com/science/article/abs/pii/S0958166904000540
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