Carbon eaters

K N and P J Harris ecoli at cix.compulink.co.uk
Sun Mar 24 08:06:29 EST 1996

> ==========
> bionet/microbiology #2377, from kafkwtz at ANDROMEDA.RUTGERS.EDU, 2399 
chars, 19 Mar 1996 10:38:19 -0
> ----------
> Article: 3328 of bionet.microbiology
> Path: 
> !kafkwtz
> From: kafkwtz at ANDROMEDA.RUTGERS.EDU (David Kafkewitz)
> Newsgroups: bionet.microbiology
> Subject: Carbon eaters
> Date: 19 Mar 1996 10:38:19 -0800
> Organization: BIOSCI International Newsgroups for Molecular Biology
> Lines: 29
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> Message-ID: <199603191835.NAA05427 at andromeda.rutgers.edu>
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> A week of so ago there was posted a question about  whether there are
> bacteria that can grow by oxidizing elemental carbon. There have been 
> responses to this interesting question. In the interest of stimulating
> discussion, I will take a shot at it.
> I know of no such bacteria and I doubt that it is possible. The 
oxidation of
> C to carbon dioxide should have more than enough energy to support 
> There are many bacteria that grow by oxidizing carbon monoxide to 
> dioxide.  Oxidation of carbon  atoms with a valence state of zero 
should be
> more exergonic than CO. The problem, I think is, activation energy.
> Elemental carbon does not exist as single atoms or small groups of 
> Carbon exists as sheets (graphite) or crystals (diamond) which are
> exceedingly stable.  There are also exceedingly insoluble, which I 
assume is
> related to the stability. Stability means much energy was given up 
when the
> structure was formed, and thererfore must be added back to crack into 
> structure.  My guess is that it is not possible  (probable ?) for this
> amount of activation energy to be added by a biological system. 
> fixation is another example along these lines. If  I rememeber 
correctly the
> reduction of dinitrogen by hydrogen is actually exergonic; yet  
biological N
> fixation has an enormous energy requirement. The triply bonded N atoms 
> so close to each other  and the electron density is so high that much 
> has to be added to get into these bonds.  Activation is costly but 
> for nitrogen, but probably too costly for carbon.
> That's my best guess. Somone correct me if i've got it all wrong.
> David Kafkewitz, Department of Biological Sciences,
>  Rutgers University, Newark N.J. 07102, U.S.A.
>  201 648 5865; fax: 201 648 1007
> kafkwtz at andromeda.rutgers.edu
Looks a pretty good try to me. Sulphur is also a problem in elemental 
form but the clever little S oxidisers have sussed the need to get S 
into solution (and hence into the cell) by using lipids. If someone can 
suggest an elemental (charcoal) C material into solution then we can 
look for an organism with that ability. Anyone know a solvent for 
elemental C ?
Peter Harris,
reading Univ. UK.

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