Growing MEthanosaeta concilii GP6

Gabriele Diekert gabriele.diekert at
Wed Apr 3 02:42:42 EST 1996

> I followed the protocol, and got
> a large quantity of black precipitate after
> making sterile additions.  The protocol said to
> add NaHCO3, vitamins, and FeCl2 aseptically
> after autoclaving.  Before these additions (but
> after autoclaving), the medium was clear.
> I suspect it is FeS that is precipitating.
> Does anyone know how to avoid this?  How can
> I measure OD if the medium always has such
> heavy ppt?  Will it affect the growth of the
> bugs?  Do Methanosaeta concilii even NEED iron?

Hi Katherine,

the precipitate for sure is FeS. What is the iron concentration of the 
medium? Is there a complexing agent present in the medium? If not, you could 
try to use NTA or a similar complexing agent to prevent the precipitation. 
All bacteria need iron, so you can't omit that from the medium.



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