Term for 'pH-tolerant'?

[TAO BRIAN T]

    I have a "dumb" question here.  While looking up journal references
in the local library database, I realized there's a property I don't
know how to describe in one word.  The subject is on methods of mutating
proteins and enzymes to make them more heat- and pH-tolerant.  The
"heat" part was easy:  "thermostability".  Is there a corresponding word
related to pH?  A search of "pH stability" didn't yield many matches I
could use.  Similary, "acidophilic" and "acidophile" didn't produce good
results either.  Any suggestions?