Growing MEthanosaeta concilii GP6

David R. Boone boone at ese.ogi.edu
Thu Apr 4 09:53:27 EST 1996

Katherine D Sauer wrote:
> I'm attempting to grow Methanosaeta concilii,
> and I can't seem to get the medium right.  I
> tried using the medium described in the paper
> which characterized the strain GP6 (which I have),
> by Patel 1984.  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.

Methanogens need iron, but not as much iron as is often  
included in their culture media.  It was once 
demonstrated (I believe in the 1970's) that large 
concentrations of iron enhanced methanogenesis and the 
growth of methanogenic bacteria, but this apparent iron 
requirement was later revealed to be a requirement for 
nickel, a trace contaminant of the iron.  If you use a 
trace metal solution that satisfies other requirements 
of Methanosaeta concilii, the amount of iron needed will 
not visibly precipitate ferrous sulfide.

Methanosaeta concilii is difficult to grow without large 
(e.g., 10%) inocula.  Even larger inocula (as high as 
50%) will give you more dependable growth.

David R. Boone
Professor of Environmental Microbiology
Oregon Graduate Institute, Portland
boone at ese.ogi.edu

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