How to screen acid producing fungi?

Jessie Micales jmicales at
Tue Mar 21 08:03:08 EST 1995

>   I have been using PDA + calcium carbonate for the screening of acid 
>producing fungi, but the outcome was not satisfied. Does anyone have any 
>effective method for the screening of acid producing fungi? Where could 
>be the possible habitat of the microorganisms? 

Many brown-rot wood decay fungi produce "tons" of oxalic acid driving the pH 
of decaying wood down below 2.0 in some cases.

There are pH indicator dyes that detect low pH that can be incorporated into 
media (assuming they aren't too fungitoxic!).   See: Green, F. III, Larsen, 
M.J., Winandy, J.E., and Highley, T.L.  1991.  Role of oxalic acid in 
incipient brown-rot decay.  Material und Organismen 26:191-213.  If you
can't find this journal, E-mail me your address and I will send you a 

So why are you looking for acid-producing fungi?

Jessie Micales (jmicales at

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