Re: ORGLIST: BioTransformation/Future?

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From: Jacob Zabicky (zabicky$##$bgumail.bgu.ac.il)
Date: Sun Dec 20 1998 - 03:22:14 EST


>Hi, All.
>
>I'm now wondering what would happen to bio-transformations in
>Organic Chemistry in the future.
>
>It has long been regarded as a volume requiring and concentration
>dependent. From that point, not so many processes have appeared to
>the industrial scale.
>
>Recently, my colleague claimed that the recent development of bio-
>technology should enable the bio-transformations to play important
>roll in the industrial process.
>He also added that the trend is now "nature identical", so the bio-
>transformations should be predominant, even if they are much more
>expensive than the conventional chemical processes.
>(C&E news also reported like this recently.)
>
>I agree that some processes are now actually in place in the
>industry (ex. lipase hydrolysis; oxidation). But most of the present
> bio-processes are based on the fermentation, not genuine
>transformations.
>I doubt the opinion that the bio-transformation will be the
>substitute to the genuine chemical reactions in future.
>
>How do you think?
>
>Any information regarding this topic (like news source) will also be
> appreciated.
>
>Thanks in advance.
>
>____________________________________________________________________
>Mitsuhiko FUJIWHARA, Ph.D.
>(Thesis title: Total Synth employing bio-transformation.)
>PGP-key http://www.asahi-net.or.jp/~bj9m-fjwr/index.html
>PGP FingerPrint [6087 4106 3402 2D84 489B 1A83 582B 7B82 F8EB 3590]
>__________________

Hello Mitsishiko!

The problems you rise in your message are very interesting and cover an
ample field. Here I would like to focus mainly on a matter of personal
opinion. You write above the prase "...are based on the fermentation, not
genuine transformations."

I think that as far as useful syntheses go you have several levels of
"chemistry" that were applied since very early times:

1. Purely biological reactors, that is, you collect your final product, or
isolate it from its biological sources. Examples: natural rubber (latex),
succrose, citric acid, morphine, sulfosaccharides, insuline, vitamin A,
penicillin.

2. Fermentors are bioreactors where you put certain microorganisms to do a
job for you under controlled conditions to optimize your yields and
kinetics. I consider these still "natural" products, but the microorganisms
were forced to act faster than in nature, or change their selectivity
towards a certain product. Examples: methane from organic wastes, citric
acid, penicillin, sulfosaccharides. Perhaps others view these products as
synthetic. It's usually a matter of taste.

3. Enzymatic bioreactors may be considered as truely heterogeneous
catalytic reactors, where you use the enzyme or enzymes that are actually
responsible for the processes described in paragraphs 1 and 2, instead of
the whole organism. Usually but not necassarily, the enzyme is immobilized
on an adequate matrix, and it acts on substrates that are more elaborate
than those used above. These reactors are potentially very effective,
because of their high selectivity and fast kinetics (practically controlled
by the diffusion of the substrate to the enzyme). Despite this potential
attractiveness, development of these processes is marred by many technical
and economic difficulties. Enzymatic reactors are developing in the
analytical direction, as biosensors. Do you know organic compounds that are
thechnically synthesized by this method?

4. Ordinary reactors. Where high throughput of inexpensive products can be
achieved in relatively small plants.

I don't see today how reactors of type 3 can replace all the others.

All the best,

Jacob

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Prof. Jacob Zabicky Tel. 972-7-6461271/6461062/6472754
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