Expert: Florence M Rollwagen - 10/23/2008

Question
Hello,
So far, I have determined that my environmental unknown is a gram negative, non motile, aerobic, cocci bacteria that grows in yellow colonies.  I believe that I have narrowed it down to the genus Phenylobacterium.  My question is: What is this bacteria's habitat and where are you most likely to find it?  and what tests could I do for confirmation?  Any feedback would be helpful and greatly appreciated!

Answer
Hi Sienna:  Thanks for your question.  Phenylobacterium is a newly isolated genus that is yellow in colony color and is a rod, a coccobacillus or a coccus (we call this pleiomorphic - many shapes).

Here is more information:
http://www.ncbi.nlm.nih.gov/pubmed/18700039

I would be cautious about naming your genus in this category.  Did you look it up in Bergey's Manual?  If so, you found that it grows very slowly, 3-4 weeks for 1-2 mm.  The colonies are tiny.  If you are far enough along in your micro course to have looked at carbohydrate metabolism, you will find that it does not use sugars.  It's optimum growth temp is 29-30 (in my micro class, the incubator is set at 37.

Here is the link for Bergey's Manual:
http://books.google.com/books?id=jtMLzaa5ONcC&pg=PA93&lpg=PA93&dq=genus+phenylob...

I would guess that your environmental unknown is Micrococcus luteus or Staphylococcus aureus.  Both are cocci and both have yellow colonies.  They are also much more common in the environment than Phenylobacterium.

Good luck!

FM Rollwagen, PhD