Growth of Yeast on Non-Fermentable CHO's

Tomas Drgon tomasd at bdg10.niddk.nih.gov
Fri Dec 15 09:42:29 EST 1995


In article <4armrk$1a8 at mserv1.dl.ac.uk>, SZABOR at fns.uniba.sk wrote:

> In article <30CCB9D5.4EAC at medcor.mcgill.ca>, Greg Cosentino
> <Cosentino at medcor.mcgill.ca> wrote:
> > Any ideas to explain growth of the yeast in
> > the absence of carbohydrate?
> 
> and Tomas Drgon replied:
> >They should not grow. I tend to think, that there are residual
> >amounts of sugars in your agar. I tried to grow wildtype yeast (S.c)
> >in liquid YPD where I by mistake did not add glucose or any other
> >carbon source, and i have got definitely NO growth.
> >On the other hand, for some yeast the carbon skeletons coming from
> >the degradation of amino acids might be enough to feed Krebs cycle to
> >produce enough NADH for respiratory chain.
> 
> >Tomas Drgon
> 
> I have to disagree. I have tried to grow wildtype Sacharomyces
> cerevisiae (W303) in liquid as well as on solid media without glucose
> or any other saccharide (complex YP or even semisyntetic YNB
> suplemented just by several aminoacids) and the yeasts did grow. A
> little bit slower, perhaps, but they did. I think they can use
> certain aminoacids (not all of them) as carbon sources. For that, of
> course, they need Krebs cycle and respiration, so petites will not
> grow.
> 
> Roman Szabo

Cau Roman.
It might depend on how dense your starting suspension is. In denser
suspensions the cells might use released metabolytes and hydrolysed cell
walls of dead cells as the source of carbon. So if you grow your inoculum,
wash with water and plate 100 cells per YP plate, do you still get
reasonable growth?
On the other hand, I know from your coleagues, that Endomyces magnusii for
example grows on plain agar with water. (might still be due to residual
sugars in agar).
BTW, how is the Warburg doing?  :))

Keep kickin'

Tomas

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