acetobacter xylinum growth rate?

Lesley Robertson l.a.robertson at tnw.tudelft.nl
Fri Aug 30 03:41:22 EST 2002


"DKafkewitz" <dkafkewitz at aol.com> wrote in message
news:20020829144803.17815.00002807 at mb-fu.aol.com...
> Emir: I do not think that would work. Pellicle growth is limited by the
surface
> area available. In tubers that is verly little  indeed.
>
> I suspect vigourous  aeration of flask cultures on a shaker might produce
> growth in suspended culture, but from what little I know of Acetobacter I
> believe  it is biofilm growth and the metablic products produced  that is
> usually of interest.

We grow biofilms on sand or pumice in tubes fed and aerated from below to
keep them mixed and suspended, with the spent medium being removed at the
top (air life reactors). Getting representative samples is a problem (we
usually have sample ports along the length but growth can be stratified).
What I've done with 1st years, which might be simple enough for a school,
was to grow a number of replicate cultures with 25 mil glass pipettes
serving as the culture tubes, and then harvest one tube for each sample .
It's not 100% accurate as there's always a bit of variation between tubes
(eg if the aeration isn't identical), but they can get the idea. Once you
have a sample, you can measure biomass by protein or dry weight
determinations (remembering to correct the latter for the sand), or even
increase in the oxygen uptake rate per unit of sample.
Lesley Robertson
http://www.beijerinck.bt.tudelft.nl






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