yeast fermentation/identification lab

Sun Feb 26 10:14:31 EST 1995

I'd like to do a college-level introductory microbiology lab on yeasts.  After 
isolating some from various places in nature, the students could get an 
appreciation of their variety (surprise - not every yeast is a S. cerevisiae) 
on the basis of colonial morphology, budding patterns, and cellular form.

I'd also like to include some easily done physiological tests, along the lines 
of the range of substrates fermented, accumulation of acids or gasses, etc.  
Can a standard bacteriological phenol-red broth with Durham tube be used for 
this?  If not, can the formula be modified, or does another medium entirely 
need to be made up?  What's the recipe for the medium, and how is it used 
(times, temps, etc.)

Are there other particularly meaningful (and easily done) physiological tests 
whose results might be expected to vary from yeast to yeast?  (Recipes?  

Finally, is there a key or other source that might let students get *some* idea 
which yeasts they might have, based on cell form, budding pattern, colonial 
morphology, and/or the results of simple physiological tests like what we're 
discussing?  I know it's too much to do a full ID, but any process of even 
partial elimination will get the point across.


Terry W. Hill
Hill at
Dept. of Biology
Rhodes College
2000 North Parkway
Memphis, TN  38112
(901) 726-3559

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