naomi-naidoo
The bacterium that I have chosen is Alcanivorax borkumensis.As an ocean lover, this is a bacterium that has saved the place I care about on numerous occasions, as it is essential in the protection of the quantity and quality of marine life. This is due to its role in the bioremediation of oil-contaminated aquatic environments. A. borkumensis produces surfactants that solubilize the oil, while other bacteria degrade the oil into carbon dioxide.
Alcanivorax borkumensis is a Gram-negative, rod-shaped hydrocarbonoclastic (“oil-degrading”) bacterium. It thrives in aerobic, halophilic environments and are found in the upper layers of marine environments such as the Pacific Ocean, Mediterranean Sea, and Arctic Sea. The significance of the bacterium is due to its role in bioremediation of oil-contaminated environments. A. borkumensis thrives in oil-polluted waters with the addition of phosphorus and nitrogen. However, due to the limited availability of these nutrients in unpolluted water, A. borkumensis is found in low numbers. The optimal conditions described for A.borkumensis growth include temperatures in the range of 20-30 degrees Celsius, and a NaCl concentration of 3-10%.
A. borkumensis is a native species and is adapted to living in oil-contaminated aquatic environments [2, 4]. Its genome encodes for a broad spectrum of efficient oil-degrading enzymes that can be used in the bioremediation of oil spills [3, 6, 9]. This provides A. borkumensis with a competitive advantage in that it can consume a wider variety of alkanes than other known species and become the dominant population in an oil-contaminated area [2]. Research is now underway to manipulate the growth of A. borkumensis with amendments of phosphorus and nitrogen fertilizers [2, 4]. Scientists are also looking to isolate genes encoding oil-degrading systems and insert these into a novel organism that can be used to remediate oil spills. However, there are risks associated with each of these methods. The addition of phosphorus and nitrogen in the form of fertilizer may further contaminate aquatic environments and aggravate environmental degradation [2, 3]. There is the possibility of rapid DNA evolution molecular evolution concerning the genomic transfer, resulting in harmful, dominant bacteria that can choke other existing species in aquatic environments [2, 3].
Created by: Jacky Chen
Published on December 2, 2017
This gives an overview of how A. borkumensis works, as well as its importance to the marine environment. Pros and cons of this bacterium are also included in the video
The microorganism's genome contains the codes of a number of interesting enzymes and it is classified as "hydrocarbonoclastic" -- i.e., as a bacterium that uses hydrocarbons as a source of energy. A. borkumensis is present in all oceans and drifts with the current, multiplying rapidly in areas where the concentration of oil compounds is high, which partly explains the natural degradation observed after some spills. The degradation of hydrocarbons using the crude enzyme extract is really encouraging and reached over 80% for various compounds. The process is effective in removing benzene, toluene, and xylene, and has been tested under a number of different conditions to show that it is a powerful way to clean up polluted land and marine environments.
This bacterium produces a whole arsenal of very effective oil-degrading enzymes. A. borkumensis' most distinctive feature is its ability to grow efficiently and almost exclusively on the hydrocarbons found in crude oil. Furthermore, it can degrade an extensive range of hydrocarbons, giving it a competitive advantage over other oil-degrading microbes. A. borkumensis _also produces biosurfactants, which help to emulsify the oil and increase the rate of degradation. _A. borkumensis' genome provides a range of systems to uptake these scarce nutrients, giving it another advantage over other microbes in oily, low nutrient waters.
A. borkumensis can use n-alkanes, aliphatic hydrocarbons, volatile fatty acids, and pyruvate as carbon and energy sources. When using only n-alkanes as carbon and energy sources, A. borkumensis produces extracellular, and membrane-bound glucose lipids termed biosurfactants. Biosurfactants are crucial to the biodegradation of oil because they reduce the surface tension of water and act as natural emulsifiers to elute oil out of the water, thereby making it available to biodegrade. However, little is known about the exact mechanism used by A. borkumensis to biodegrade oil, a hypothesis summarizes the method with the following steps: 1.) oil leakage into aquatic environments causes an increase in phosphorus and nitrogen concentrations 2.) increased nutrient availability causes A.borkumensis to metabolize and grow faster; population increases 3.) A.borkumensis attaches and forms a biofilm around the oil droplet. The biofilm aids in the recruitment of additional bacteria to the site of contamination 4.) AlkB1 and AlkB2 enzymes are synthesized and are used to oxidize C-alkanes, thereby catalyzing the degradation of oil 5.) Biosurfactant produced and breaks oil and water emulsions to make oil more readily available for A.borkumensis
