Nature's cleanup crew
In the hot, arid region of central Myanmar's Magway Region lies the Taungdwingyi oil field, part of the larger Salin Sub-basin. This area is characterized by natural oil seeps, places where crude oil from underground reservoirs leaks to the surface. These seeps create an extreme environment, saturated with toxic hydrocarbons. Yet, within this seemingly inhospitable oily substrate, a complex and specialized microbial ecosystem thrives. These microorganisms survive and actively consume the crude oil as their primary source of carbon and energy.
Researchers have identified diverse communities of bacteria and archaea at these sites. These are not ordinary microbes. Generations of exposure have selected for species with unique metabolic capabilities for breaking down the complex molecules in petroleum. Among the species are bacteria from genera like Pseudomonas, Bacillus, and Acinetobacter, which are known for their ability to degrade hydrocarbons. These organisms carry out biodegradation, a process where they use enzymes to break down large hydrocarbon molecules into smaller, less harmful compounds. This natural process is a form of bioremediation.
The biosurfactant solution
One of the main challenges for microbes consuming oil is that oil and water do not mix. Hydrocarbons are hydrophobic, making them difficult for bacteria to access and absorb. To solve this, many of the bacteria at Taungdwingyi produce their own detergents, called biosurfactants. These are amphiphilic molecules, meaning they have both a water-loving (hydrophilic) and an oil-loving (hydrophobic) part.
These biosurfactants reduce the surface tension between the oil and water, breaking the oil slick into microscopic droplets. This emulsification dramatically increases the surface area of the oil, making it much more available for the bacteria to consume. Some of the biosurfactants identified in similar environments are rhamnolipids and sophorolipids, which are glycolipids. These naturally-produced compounds are highly effective and have significant advantages over synthetic chemical dispersants used to clean up anthropogenic oil spills. They are biodegradable, have lower toxicity, and can be more effective under a wider range of environmental conditions. The unique microbial communities at Taungdwingyi contain genetic information that could lead to new, greener technologies for cleaning up pollution.