[Digestion] Attachment to previous Article - More scientific based research and questions

Duncan Martin duncanjmartin at gmail.com
Mon Oct 18 00:53:27 PDT 2010


Perhaps Dr Karve & I should agree to disagree?

To argue that dung is not food for the methanogens because they need help to
digest it is really a semantic quibble. It misses the point I was responding
to - that the digestion process is not *completed *by the act of
defaecation, it is merely *terminated* for the owner of the gut in question.

I have never seen any serious literature suggesting that microbes are
altruistic. However, the principles of commensalism are well established and
I see no basis for dismissing them. Moreover, the complex web of metabolic
interactions in AD has been extensively researched and is pretty well
understood - though I am sure there is more to discover.

Nor have I seen any literature whatsoever suggesting that the methanogens
consume other microorganisms. I would be intrigued to see a proposed
mechanism.

To dismiss all the textbooks as wrong (see previous postings) is unhelpful,
at best. Who could only say that unless he had read every one of them? Of
course, there are mistakes - even in the best books - if only because
science moves on, so any book becomes outdated. And there are indeed some
layman's guides to AD that include some odd ideas - but who would take them
as serious guides to the science?

When we find such errors, let us use this forum to report them - giving
exact references. But lets not confuse newcomers to the field by dismissing
every other source of information as rubbish.

Finally, let us accept that each of us is entitled to his opinion - but lets
reserve this forum for the fruits of practical experience and evidence-based
information.

I suggest we draw a line under the present debate.

Duncan Martin, PhD, MCIWM, MIChemE, MIEI
Cloughjordan Ecovillage
Ireland

On 17 October 2010 16:39, Anand Karve <adkarve at gmail.com> wrote:

> Dear Duncan,
> I dont believe in the theory of a chain of micro-organisms, with one
> species converting the cellulose into glucose, another converting the
> glucose into an organic acid (e.g. citric acid), still another converting
> the organic acid into acetic acid and ultimately the acetic acid being
> converted by the methanogenic organisms into carbon dioxide and methane. If
> this were true, one would have by now isolated the organism that converted
> cellulose into glucose and used the glucose to produce alcohol. Cellulose is
> the most ubiquitously found organic compount in the world and with this
> simple process, one would have produced unlimited quantity of liquid fuel.
> But even today, the conversion of cellulose into glucose is achieved in any
> industrial process by using a cellulolytic enzyme extracted from a
> cellulolytic organism. The reason for this is, that the glucose converted by
> the organism from cellulose is consumed by the same organism. And once it is
> consumed by an organism, it is converted into its cell all the way down to
> carbon dioxide. The micro-organisms in the gut of an animal cannot be
> expected to be so altruistic as to predigest the food and suply it to the
> methanogens. I feel that the methanogenic organisms consume the fellow
> micro-organisms in the gut of animals and digest them to produce methane and
> carbon dioxide. Such dog-eat-dog reactions occur also in the soil supplied
> with organic matter.
>         In any case, once it is accepted that the methanogenic organisms do
> not digest the dung directly and that they need the help of other organisms
> to digest it, one cannot accept that dung is the food of the methanogens. It
> is like saying that manure applied to a field is human food, because through
> a number of biological processes it ultimately ends up into products, which
> the humans eat.
> Yours
> A.D.Karve
> On Fri, Oct 15, 2010 at 4:27 PM, Duncan Martin <duncanjmartin at gmail.com>wrote:
>
>>
>> Yes, the gut methanogens do, in a sense, eat what the animal eats.
>> However, it would be more accurate to say that their diet is derived from
>> what the animal eats. The methanogens in the gut of a cow are surrounded by
>> celluose and other biopolymers but they cannot digest them. They live on the
>> waste products of other microbial processes. The web of metabolic
>> interactions is well known.
>>
>> Where I would "hoot out" Dr Karve is his belief that dung cannot serve as
>> food for the methanogens because they are "thrown out" of the body along
>> with the dung. I don't understand the logic here.
>>
>>
>>
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