pH problem

[Tien-Hsien Chang]

     We are studying a particular drug resistance/sensitivity of the budding 
yeast.  We noticed that the pH of the yeast culture in minimal medium 
supplemented with required amino acids drops substantially to nearly 3.  This 
created a problem for us, as the drug may get inactivated or converted to other
chemical forms at such a low pH.

     Is there any well-established protocol to buffer the SD (synthetic 
dextrose) medium, both liquid and solid, allowing pH to be maintained at 7.0 in
the culture ?  Any other relevant information or references will be greatly 
appreciated.


                              Tien-Hsien Chang
                              Assistant Professor of Molecular Genetics
                              The Ohio State University
                              484 W. 12th Ave.
                              Columbus, OH 43210, USA
                              (614)-292-0631
                              (614)-292-4466 [fax]