Hi Ama,
I agree that ATCC charges a lot for their cultures but they guarantee purity which requires a lot of technical work. I can think of two possible ways for you to get a culture of D. acidovorans. You can look on PubMed for publications about D. a., get the names and affiliations of those doing the research and call them. Someone might be willing to help an aspiring high school scientist and send you a culture of the bacterium. I took a quick look through the publications and they all isolated D. acidovorans themselves using selective media. That brings me to the second way to get the bacteria--isolate it yourself from soil. According to what i read, D. acidovorans is a common inhabitant of water and soil. I did a search for how to isolate bacteria from soil and found several methods. Here's a good example but there are many others:
http://www.ehow.com/how_6918955_do-isol ... soil_.html
There are methods for isolating specific types of bacteria from soil but I have never done that. Since you are looking for a bacterium that digests petroleum, you could try spreading a
small amount of oil on top of the agar in a Petri dish and see what grows. Here's one recipe I found for preparing agar for soil bacteria:
http://bugs.bio.usyd.edu.au/learning/re ... ipes.shtml
Add 5 g of good garden loam [no pesticides, chemicals or fertilizers!] to 1 liter of distilled water, shake it well and let the mixture settle for a couple of hours. Carefully pour the liquid into a funnel plugged with a cotton ball and collect the filtrate. Add 20 g of plain agar, autoclave the mixture and pour the plates.
The main problem with isolating bacteria yourself is identifying what bugs you have. A research lab would simply isolate DNA from the bacteria, sequence part of the genome and do a search of the bacterial database to ID the type. Unless you will be working in such a lab you would not be able to do this. So, if you want to specifically experiment with D. acidovorans, you'll have to find someone who is willing to give you a culture.
Are you familiar with growing and handling bacteria, making dilutions and plating on agar? Do you have access to a microbiology lab to do your experiments? It would be best to do your experiments in your school biology lab because many bacteria, including D. acidovorans, can be harmful to humans.
Try to find a lab that will give you a culture of D. acidovorans--you can offer to pay for the shipping. If you do decide to try to isolate bacteria from soil, we can help you with the details. I think you have a great idea and we want to see you succeed in testing it.
Good luck!
Sybee