The Influence of Biosurfactants on the Rate of Oil Spill Bioremediation BIOLOGICAL RESEARCH PROJECT...
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Transcript of The Influence of Biosurfactants on the Rate of Oil Spill Bioremediation BIOLOGICAL RESEARCH PROJECT...
The Influence of Biosurfactants on the Rate of Oil Spill BioremediationBIOLOGICAL RESEARCH PROJECT
BY EMILY MA
Introduction
Problem: Petroleum oil is a significant source of nonrenewable energy that contributes to sustaining society; however, an oil spill can have disastrous effects on the biodiversity and productivity of a marine ecosystem.
Solution: Bioremediation is an oil spill treatment that uses naturally occurring organisms to break down toxic substances into less hazardous ones. Bacteria play a crucial role in the biodegradation of oil by producing biosurfactants.
Competing Technologies
Other methods that control oil spills include a variety of booms, barriers, and skimmers, as well as natural and synthetic absorbent materials
These methods work by physically removing the oil from the body of water
However, these methods are inefficient because they are not cost-effective, they require high maintenance, and these processes occur at a slow rate
A disastrous oil spill occurring in the Gulf of Mexico, which killed thousands of marine organisms and had lasting effects on the environment
Limiting Factors to Bioremediation
TemperatureLow temperatures can hinder the biodegradation process because molecules move at a slower rate, and the impact of some molecule collisions would not be strong enough to bring about a reaction.
OxygenOxygen is also necessary because it is needed for aerobic hydrocarbon degradation reactions, one of the processes essential for bioremediation.
Nitrogen and PhosphorusIn addition, bacterial metabolism requires certain amounts of nitrogen and phosphorus as sources of nutrients.
Physical Status of an Oil Spill
The distribution of oil in the water spreads throughout the depth of the ocean.
• The lighter potion of the oil normally spreads and forms a thin layer on the top of the body of water
• Most of the oil emulsifies and dissolves in the mid-potion of the water.
• Some denser potions of oil sink to the bottom of the ocean. The release and distribution of oil in the water column due to the differences
in physical status and density of the oil that was released
Oil degrading Bacteria
Types of Bacterial Biosurfactants
Low molecular weight Structure-usually glycolipids, in which
carbohydrates are attached to a long chain of aliphatic acid or lipopeptides
Benefits-efficiently lowers surface and interfacial tension and has a high specificity
Setbacks-Cannot bind tightly the surface molecules and less effective in preventing the combination of oil molecules
High molecular weight Structure-this kind of bacterial
biosurfactant are composed of polysaccharides and other high weight molecules
Benefits-Efficient at coating oil droplets, prevents coalescence of oil, and has a high specificity
Setbacks-less effective at reducing surface tension
Design
Since high molecular weight and low molecular weight biosurfactants essentially do different tasks, creating genetically modified bacteria that would produce both types of biosurfactants would increase the rate of bioremediation.
Producing a bacteria that can synthesize and regulate the production of rhamnolipids (a low molecular weight biosurfactant) and alasan (a high molecular weight biosurfactant) would be a very effective way to treat oil spills
Types of Biosurfactants Used
Alasan This biosurfactant is composed of an
anionic polysaccharide and a protein with a high molecular weight and is covalently bound to alanine, an enzyme
Alanine plays an important role in the structure and function of alasan
Allows this biosurfactant to become more effective in stabilizing oil emulsions and in solubilizing hydrocarbons
Rhamnolipids Rhamnolipids are a class of glycolipid
produced by multiple species of Pseudomonas and it has a low molecular weight
Pseudomonas aeruginosa has the ability to metabolize an array of substrates, including n-alkanes, hexadecane and oils
The rhamnolipids are able to emulsify the oil and lower interfacial, and in turn, increase the rate of uptake in bacteria
This system consists of the following parts
gene that enables the cell to produce rhamnolipids
gene that enables the cell to produce alasan
a sensor that would detect the presence of hydrocarbons in the oil spill (Lacl)
a regulator to transform the signal and activate the promoter (IPTG)
promoter to turn on the gene
open reading frame (Plac) that will ultimately produce alasan
a sensor that would detect the presence of alasan
a regulator to transform the signal and activate another promoter
another promoter to turn on the gene
open reading frame that will produce rhamnolipids
the terminating sequence
Pseudomonas aeruginosa
Under the Presence of Hydrocarbons:
1)The hydrocarbon sensor is stimulated
2)IPTG is activated and it transforms the signal
3)This activates the promoter
4)The Plac gene is turned on and it starts to produce alasan
Hydrocarbon sensor (Lacl)
Presence of hydrocarbons
Regulator (IPTG)
Open reading frame (Plac) on
Alasan is produced
Under the Presence of Alasans:
1)The alasan sensor is stimulated
2)The regulator is activated and it transforms the signal
3)This activates the promoter
4)A certain gene is turned on and it starts to produce rhamnolipids
Alasan sensor
Presence of alasan
Regulator
Open reading frame on
Rhamnolipids are produced
• when there are no hydrocarbons present, then no chemical reaction would take place and neither alasan nor rhamnolipids would be produced
• when there are hydrocarbons present, both alasan and rhamnolipids would be produced.
• when there are no hydrocarbons present and alasan is present, rhamnolipids would be produced
Hydrocarbon
s
Alasan Rhamnolipid
s
0 0 0
1 1 1
0 1 1
Truth Table
Potential Problems
One of the main problems in this design is the possibility of Pseudomonas aeruginosa overpopulating and an algae bloom occurring
In addition, there could be a problem with the design if there is a surplus of alasan and rhamnolipids are continuing to be produced without the presence of oil
Overall there is a low risk factor for this design, and it is a quick and efficient way to speed up the rate of oil spill bioremediation
Conclusion
Biosurfactants are produced by a vast array of oil-degrading microorganisms
These biosurfactants can have a low molecular weight, and decrease the oil-water interfacial tensions, or they can have a high molecular weight, and act as biodispersants by preventing the coalescence of oil droplets in the water
These biosurfactants simulate the growth of oil-degrading bacteria and improve their ability to utilize hydrocarbons
Bibliography
http://www.researchgate.net/publication/6424393_Molecular_and_structural_characterization_of_the_biosurfactant_produced_by_Pseudomonas_aeruginosa_DAUPE_614
http://repository.ias.ac.in/17365/1/409.pdf
http://www.iisc.ernet.in/currsci/jul10/articles19.htm
http://www.sciencedirect.com/science/article/pii/S0960852415006604
http://microbewiki.kenyon.edu/index.php/Oil_spills
http://dujs.dartmouth.edu/winter-2012/oil-spills-severity-and-consequences-to-our-ecosystem#.VZPqbPlViko
https://en.wikipedia.org/wiki/Rhamnolipid
http://parts.igem.org/Part:BBa_K398206
http://www.epa.gov/oem/content/learning/oiltech.htm