ivor & olive lewis on mon 2 nov 09
Dear Friends,
Appended below are two extracts from a paper published in 1992
Reference is APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Sept. 1992, p.
3130-3135
Ceramic material tested was Aluminium Oxide. If Bacterial Residues are
causing dispersion and reducing the effective viscosity of a suspension the=
n
it seems logical to suppose that using biologicals will destroy not enhance
the plastic quality of potter's clay
Glick's paper Ref (7) makes interesting reading.
Best regards,
Ivor Lewis,
Redhill,
South Australia
<
from A. vinelandii cultures was tested for its ability to act as
a dispersant by preparation of 2% (vol/vol) suspensions of
alumina particles. The resulting wet particle-packing densities
showed clearly that bacterial alginate was an effective
dispersant (allowing for increased wet packing density relative
to the control) and acted in a manner similar to that of
kelp alginate (Fig. 1). The maximum wet packing density
occurred with a 0.5% concentration of the alginate (dry
weight basis of polymer to particles) for both alginates.>>
<
pottery manufacture with natural clays could benefit
from a fuller understanding of the microbiology of the aging
process. Perhaps the use of appropriate bacterial inocula,
carbon sources, and other nutrients could improve polymer
production, dramatically hasten the seasoning process, and
make it more reproducible and efficient, like commercially
controlled alcoholic and lactic fermentations.>>
Jess McKenzie on mon 2 nov 09
Interesting, Ivor.
Near as I can determine, A. vinelandii is
Azotobacter vinelandii
Its biosafety level (BSL) is 1, and it is available from
American Type Cultures for about $240.
A more economic producer of alginates might be one of the
Pseudomonas species, but several of them are BSL 2. P.
aerugenosa, a fairly common lab contaminant, is an
opportunistic pathogen.
I'd be careful about using either species--the alginates these
bugs produce are thought to make them (the bugs) resistant to
the host immune system and to antibiotics. This is especially
true in cases of cystic fibrosis. Mortality in those cases is
about 50%.
There's no doubt, apparently, that aging clay will increase
plasticity, but I would not use either species for that
purpose.
~jess
ivor & olive lewis wrote:
Appended below are two extracts from a paper published in
1992
Reference is APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Sept.
1992, p.
3130-3135
Ceramic material tested was Aluminium Oxide. If Bacterial
Residues
are causing dispersion and reducing the effective viscosity of
a
suspension then it seems logical to suppose that using
biologicals
will destroy not enhance the plastic quality of potter's clay
Glick's paper Ref (7) makes interesting reading.
Best regards,
Ivor Lewis,
Redhill,
South Australia
<
from A. vinelandii cultures was tested for its ability to act
as
a dispersant by preparation of 2% (vol/vol) suspensions of
alumina particles. The resulting wet particle-packing
densities
showed clearly that bacterial alginate was an effective
dispersant (allowing for increased wet packing density
relative
to the control) and acted in a manner similar to that of
kelp alginate (Fig. 1). The maximum wet packing density
occurred with a 0.5% concentration of the alginate (dry
weight basis of polymer to particles) for both alginates.>>
<commercial
pottery manufacture with natural clays could benefit
from a fuller understanding of the microbiology of the aging
process. Perhaps the use of appropriate bacterial inocula,
carbon sources, and other nutrients could improve polymer
production, dramatically hasten the seasoning process, and
make it more reproducible and efficient, like commercially
controlled alcoholic and lactic fermentations.>>
ivor & olive lewis on tue 3 nov 09
Dear Jess McKenzie,
There were two issues of concern beyond infection problems.
1. The mineral used as a test subject would be regarded as a non plastic
when mixed with water.
2. Conclusions about plasticity described the effect of the alginate
residues as causing dispersion. This seems to be contrary to the notion tha=
t
plastic clay mixtures are Agglomerates or Aggregates.
Why not use boiled Kelp or one of the Sea Wracks ?
Thanks for your information.
Best regards,
Ivor
Jess McKenzie on tue 3 nov 09
Ivor
I placed that warning just in case someone thought to
buy, say a Pseudomona culture, and innoculate their
clay. Not needed, in my opinion, because there are
plenty of wild bugs out there already in the clay.
Most materials, e.g. grapes, wheat, collect the
microbes that feed on them, giving us wine,
sourdough, and plastic clay.
As to additives (kelp, etc) I suspect there are
plenty ,including alginates, in commercial clays.
Joan and I are now trying a ^6 clay that feels
"snotty," as one of our Listers would call it. We
checked the MSDS (always a good idea!) and found
nothing about organic additives. I msg'd the seller,
asking *only* if he had included *any* organics--not
for their identity. I took no response as an
affirmative.
To be clear, I see no hazard, absent unusual
sensitivity or allergy, to the use of alginates. But
adding bacteria suspected to be pathogens is risky,
expensive, and a helluva lot of trouble. Blending
the right clays seems a better way to go.
Best regards...~joan and jess
.........................................
Ivor Lewis wrote:
... There were two issues of concern beyond infection
problems.
1. The mineral used as a test subject would be
regarded as a non
plastic when mixed with water.
2. Conclusions about plasticity described the effect
of the alginate
residues as causing dispersion. This seems to be
contrary to the
notion that plastic clay mixtures are Agglomerates or
Aggregates.
Why not use boiled Kelp or one of the Sea Wracks ?
Thanks for your information.
Best regards,
Ivor
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