hroychow at NMSU.EDU
Wed Jun 26 10:58:58 EST 1996
On Tue, 25 Jun 1996, Michael Casey wrote:
> I am studying the rate of growth of Clostridium tyrobutyricum in acid medium
> and have found them to be very sensitive to the presence of oxygen. I follow
> the growth rate by measuring the turbidity at 650 nm. I have tried using
> different techniques to reduce the oxygen content of the medium but with
> little success.
> Gassing with CO2 does not reduce the oxygen content sufficiently.
> The addition of cysteine to the medium is also not sufficient but the
> presence of sodium thiogllycolate inhibits growth.
> The addition of Oxyrase, a commercial enzyme preparation which removes
> oxygen, causes turbidity and prevents accurate measurement of growth.
> Does anyone have an idea how I could reduce the oxygen content of
> the medium without causing turbidity?
> Thank you.
> Michael Casey
> Swiss Federal Dairy Research Institute
> 3097 Liebefeld
> Tel: (+41) 31 323 81 79
> FAX: (+41) 31 323 82 27
> email Michael.Casey at fam.admin.ch
For anaeobic bateria, we used to use a purging attachment. One may use a
two-holed rubber stopper fitted with one delivery and one sampling
tubing. The delivery tube is used to purge N2 through the flask at
regular intervals. IMO, use of CO2, unless recommended as in CO2 incubators
for animal cell cultures, is not a good idea since it will depress the pH
of the medium.
Hiranya S. Roychowdhury
Plant Genetic Engineering Lab.
Box 3GL, NM State Univ.
Las Cruces, NM 88003
Phone: (505) 646-5785
hroychow at nmsu.edu
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