What are the effects of these conditions on fermentation?

[undisclothesed]

we did a lab the other day on the effects of ph, substrate (lactose), MgCl2, NaF, and temperature on yeast fermentation.

I can understand how NaF (an inhibitor) would decrease fermentation rate.

What I don't understand is how pH levels, MgCl2, and temperature effect yeast fermentation..?

I've been googling for the past hour and can not come up with any answers Can someone please help me out?

[Nithin]

For every organism in the world, there is particular temperature and pH where its activity is maximum.

For yeast I think it should be around 30 degC and its pH requirement is acidic condition (not very much)

[undisclothesed]

can you exlain how exactly temperature and ph effects the yeast?

[Poison]

It's generally about the enzyme activity.