Xref: utzoo sci.chem:2009 sci.bio:3602
Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!wuarchive!zaphod.mps.ohio-state.edu!ub!kitty!larry
From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: sci.chem,sci.bio
Subject: Re: Thermodynamics of reduction of phosphate to phosphine
Summary: Some further considerations...
Keywords: marsh gas, wierd organisms
Message-ID: <4072@kitty.UUCP>
Date: 1 Oct 90 02:25:08 GMT
References: <60883@iuvax.cs.indiana.edu> <4067@kitty.UUCP> <61152@iuvax.cs.indiana.edu>
Organization: Recognition Research Corp., Clarence, NY
Lines: 68

In article <61152@iuvax.cs.indiana.edu>, chiaravi@copper.ucs.indiana.edu (Lucius Chiaraviglio) writes:
> >> 	Something that has intrigued me (and some microbiologists) for a while
> >> is the process, so far as I know almost completely uncharacterized, of
> >> phosphine production in marshes.  [. . .]
> >
> >	It is my belief that an explanation of the mechanism behind the
> >biological production of phosphine requires consideration of the various
> >processes involved in putrefaction.  It is also my feeling that there
> >exists more than one putrefactive mechanism for the production of phosphine.

	Congratulations, Lucius.  You have posed a problem which has been
bugging the hell out of me for the past two days!  As if I didn't have
enough work and other things to occupy my time...  :-)

	I should have some more to say on this issue in a day or so.  In the
meantime, here are some random thoughts going through my mind:

1.	Some extensive studies which *might* offer suggestions as to the
	mechanism for biological production of phosphine deal with the
	biochemistry and microbiology of the rumen.  Take a look at a copy
	of "Dukes' Physiology of Domestic Animals" and you might see one
	path of my reasoning.  This book is well endowed with literature
	references.  I have used literature on the rumen to find answers
	not available elsewhere to questions on industrial fermentation
	matters, and on the toxicology and metabolism of methane.

2.	I may have been too hasty in dismissing the possible role of
	hydrogen as a reducing agent (as you originally suggested).
	Consider that in the rumen, virtually all of the hydrogen formed
	through bacterial action is used to reduce CO2 to methane.
	This surpised me, for various reasons.

3.	There is some similarity beteen phosphine and ammonia.  So, I
	got to thinking about NADPH and ferredoxin.  Ferredoxin is quite
	a respectable reducing agent.  Consider, as an example, that
	ferredoxin possessed by certain anaerobic bacteria can readily
	form pyruvate from reductive carboxylation of acetate (plus CO2).

4.	If we can establish the biological formation of hypophosphorous
	acid, then I might have a mechanism which to explain phosphine
	production.

5.	Something about mevalonic acid and the geranium plant is ringing
	a bell.  This is really a *bizarre* thought:  could the geranium
	plant somehow produce a small amount of phosphine as part of its
	characteristic odor?

> (Hey, isn't thinking up biochemical pathways
> and their reaction mechanisms fun?)

	Yup! :-)

> >	While most biological phosphorous is in the form of phosphate
> >esters and diesters, there are some exceptions.  Consider as an example,
> >2-aminoethylphosphonic acid, which is found in some protozoa.
> 
> 	Anyone know what this does for those protozoa, or how they make it?

	No, but I found two references: (1) M. Horiguchi and M. Kandatsu,
"Nature", 184, 901 (1959); and (2) L. D. Quin, "Topics in Phosphorous
Chemistry", 4, 23 (1967).

	Now, if I could only find a reference to explain the production
of phosphine... :-)

Larry Lippman @ Recognition Research Corp.  "Have you hugged your cat today?"
VOICE: 716/688-1231   {boulder, rutgers, watmath}!ub!kitty!larry
FAX:   716/741-9635                  {utzoo, uunet}!/      \aerion!larry