> 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.
Regards,
Gabi
