A review of: Lü, J. C., Li, Z. T., Hussain, K., and Yang, G. K. (2011) Bioremediation: The New Directions of Oil Spill Cleanup. Middle-East Journal of Scientific Research 7(5): 738-740
Oil pollution is an increasing concern, particularly with the ever increasing demand. With this increasing level of pollution, an effective solution for the environment is required; bioremediation is one such effective method. This paper looks at current knowledge in bioremediation including its techniques, advantages and disadvantages, particularly as a pollution control mechanism.
Bioremediation is the breakdown of dangerous or hazardous chemical and contaminants using microorganisms to break down and detoxify by transforming them into less harmful substances. This can take advantage of a naturally occurring metabolic pathway or through the genetic modification of the microorganism. Bioremediation can be used both in marine and terrestrial pollution and can take place in-situ (treated at the site of contamination) or ex-situ (the contaminated material is removed for treatment elsewhere). For marine environments, in-situ treatment is the only really viable option in most circumstances. Bioremediation can also be done both aerobically (through the addition of oxygen either by injection or the addition of nutrients) and anaerobically. Techniques outlined in this paper include; bioangmentation (involves the addition of microorganisms that can degrade a particular contaminant, biostimulation (the addition of nutrients to increase the level of activity) and bioventing (the addition of oxygen).
The advantages of bioremediation generally outweigh the disadvantages. The authors state that bioremediation is generally more economical than using other methods of treatment since it can be performed in situ and, in marine environments, there are plenty of microorganisms present for bioremediation to occur. It also has the advantage of being a natural process and therefore is expected to have minimal environmental impact. However, bioremediation may not be an instantaneous process, mostly it isn’t. It can take weeks or months depending on the amount of pollution and additional nutrients and/or microorganisms may be required for this method to be effective. As well as this, some contaminants may not be biodegradable, limiting the practical uses of this method.
Bioremediation is therefore an effective, low cost, naturally occurring method that can be of particular use in certain circumstances of pollution, such as in the marine environment. However, its scope of use is limited and so can only really be used for certain types of contaminants, such as oil pollution. The authors mention the use of microorganisms to degrade metals and research on this would certainly be valuable to increase the usefulness of this method and to help introduce methods of pollution control that are ‘environmentally friendly’.
7 comments:
Hi Rachel,
This is a really relevant topic, do the authors suggest the concentration of oil that it works best on? this would be really beneficial for oil leaks (from ships etc) if it could break down the pollutants rapidly, do the authors suggest how they can improve or further research the mechanisms involved?
Yes I'm very interested in this area as well, it was mentioned to me last night from a mate that study Botany that although it may be an option for marine environments, plant bioremediation is a lengthy process and often gets over looked. In relation to marine microbes I wonder if, as a consequence of the introduction of microbes into ecosystems weather post clean up it would create perpetuating shifts in microbial community composition.
Hi Dan
Unfortunately, the authors do not answer any of your questions. Another study on bioremediation, suggests that bioremediation is more effective on lighter concentrations of oil. It suggests that bioremediation and biodegradation is never 100% effective as the microbial population has never been observed to degrade 100% of oil pollution, particularly if the oil spill is of higher concentration. In the case of the BP Deepwater Horizon exploratory well spill in 2010, roughly 205.8 million gallons of oil and gas escaped into the surrounding waters and (as far as I can tell) only 16% of the spill was degraded or naturally dispersed, at least initially. Other methods of treatment were used alongside, including burning and chemical dispersion. Perhaps this is one reason why bioremediation is often overlooked or used as only part of a treatment operation.
Reference: Atlas, R. M., and Hazen, T. C. (2011) Oil Biodegradation and Bioremediation: A Tale of the Two Worst Spills in U.S. History. Environmental Science and Technology 45: 6709-6715
Thanks Rachelle I'll check out the reference, that was one of the examples I was thinking of too.
That reference is really interesting at looking at how bioremediation was and can be used in real oil spill cases, which i have reviewed earlier, and to see how effective it really is when put into practice.
In response to Corin, the idea that existing microbial communities would shift due to the addition of microorganisms for the treatment of pollution is a really interesting one. It would make sense that the addition of microorganisms would affect the populations of those that naturally occur. It was clear from the paper referenced above that the indigenous microbial community in both of the cases described certainly shifted due to the oil spill itself with an increase in the oil-degrading bacteria, as you might expect, but I have not yet been able to find any research that looks at the effect of the addition of microorganisms to the existing community. An interesting point for further research.
It would be very interesting to know the type of oil that was used in this, as in a paper that i have recently read, some oil reducing microbes are specific to a certain type of blended oil, such as the P. pseudoalcaligenes only mineralising compounds found in Tapis blended oil which is rarely found outside Malaysia.
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