Aluminium tolernant fungi

Tryggvi Emilsson emilsson at
Tue Feb 11 13:02:05 EST 1997

On Thu, 6 Feb 1997, Robert Corkery wrote:

> I am baffled by a fungus that has grown on a soap containing about 30 wt % 
> Aluminium. Is this of interest to anyone?
> If so, please let me know by email.
> Rob Corkery
> Australian National University

I am just as baffled about how any soap could contain 30% aluminum.
Any water soluble aluminum compound (eg. Al2(SO4)3 ,AlCl3,etc)contain
less than 30% aluminum, the balance being the counter-ion.The only
way to get the aluminum content up to 30% would be to mix soap with
powdered aluminum metal,or with aluminum oxide. In either of those forms
the aluminum is virtually insoluble and thus of no concern to fungi that 
might be snacking on the stuff.
Even if the 30% is a typo (ie, should be 3%,or .3%),aluminum could not 
be kept in solution in soap. If the soap in question is the typical fatty
acid salt the aluminum would form an insoluble carboxylate (eg. aluminum
tri-stearate).If the "soap" is an alkylsulfonate detergent,with a pH
somewhere between 6 and 9, the aluminum would form an insoluble hydroxide.
It is true that water soluble aluminum compounds are noxious to living
organisms.They curdle proteins,hence the usefulness of styptic pencils and
antiperspirants.Generally,few aluminum conpounds will stay in aqueous
solution at a physiologically compatible pH. (otherwise Roll-Aids would
be acutely toxic...).

U.of Illinois/Chemistry  

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