|MadSci Network: Microbiology|
To begin with lets break this down into its constituents, oil and microorganisms. Oil is an energy source to us humans but we do not view it as a food. What is a food ?. Well we consider food things like sugars etc. but the difference between these compounds and crude oil is basically non- existent, they both are energy and carbon rich. Just because we can not use crude oil (remember we can use other oils such as olive oil as energy sources) we dismiss it as not a food. So what is crude oil ? Well itís a very complicated mix of a wide variety of carbon compounds from cyclic and polycyclic hydrocarbons (benzene, napthalenes etc.) to straight chained aliphatic compounds such as heptane and octane. To us its toxic, to a number of microorganisms its just like candy. So how can microorganisms use it and we can't? Well it all breaks down to diversity, evolution and biochemistry. Microorganisms are a very diverse group. Animals and plants are nearly identical to one another when you compare how different microorganisms are. They have been on this planet for over 3 billions years, we as humans only 1 million. They have adapted (evolved) to use all the available nutrients they can and some individual species (Pseudomonas) can use up to 1000 different carbon compounds. What do they do with the oil ? Well basically they eat it just like you eat cereal. They use enzymes to break it up (metabolize it) using O2 turning it into CO2 and more microorganisms. Itís the initial enzymes that are special. They break down the petroleum substituents into smaller molecules that can enter central metabolism. Central metabolism then routes these chemicals to make energy, and materials for new cells (this is just the same as you). Three years ago I was lucky to meet one of the people who used microorganisms to clean up the Exxon Valdez spill. The beaches treated with microorganisms were cleaned much more effectively and faster than the ones they used detergents etc on. What they were actually doing was merely enhancing the natural process. Ever think where that oil goes over the years. Well the microorganisms eat it. Try it some time. Take some old oil (0.1 ml) and add 100ml of tap water to it. Leave it open to the air and watch what happens, shake it about once or twice a week. Give it a few weeks, microorganisms will grow probably pseudomonas and fungi. So to conclude they metabolize oil just like a food to carbon dioxide and new cell material (more microorganisms), they are naturally present everywhere but some have been genetically modified by industry to be better at doing it, and they can do this because of the enzymes they produce.
Try the links in the MadSci Library for more information on Microbiology.