need help with nutrients for bacteria !

Tony Stott tony.stott at
Wed Nov 24 00:48:03 EST 1999

Have you thought about the pH or the calcium level of the water, it
could be calcium phosphate or some other low solubility phosphate
precipitating out because of the "hardness" of the water.

Tony Stott
Department of Microbiology
Monash University

Franz H. Wagner wrote:
> I am working on experiments with enriching natural streamwater (surface
> water) with nutrients (glucose, nitrate, phosphate) to test the effect
> on surface attached bacteria (biofilms). My problem is, that whem I am
> adding a concentrated nutrient solution to the stream water the
> phosphate (sodium phoshate x 12 H2O) is immediately falling out in form
> of "flocks". It appears under the microscope that these flocks have a
> particular center - a cristal or a bacteria probably ? Filtering the
> water (0.01 mm) does not help.
> The same thing is NOT happening if I dissolve the nutrients in tap water
> or destilled water.
> Does anybody of you have an idea what I should do ? Is there another
> phosphate which would do the job better ? Could the bacteria use NaHPO4
> as well (better soluble - no flocks) ?
> Sorry for my bad english and for my un-knowledge in chemistry and
> microbiology. I am not a microbiologist myself, but a
> limnologist-zoologist - and I do these experiments to see which effect
> the influenced biofilms may have on invertebrates living in streams.
> Thanks in advance for any help and suggestion
> Franz
> --
>      Franz H. Wagner, Biological Station Lunz
>      3293 Lunz am See, AUSTRIA
>      TEL: ++7486  8095 24 FAX: ++7486  8095 31
>      e-mail: franz.wagner at

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