purple non-sulfur bacteria

[prime]

Hello.
I am in desperate need of some advice regarding an experiment.
I am testing the purple non-sulfur bacteria Rhodospirillum rubrum.

My aim is to compare the rate of growth of the bacteria using light and
fermentation for energy metabolism.

But, should I be testing just fermentation(dark cupboard with sugars) vs just light (U.V light box, no sugars. Or should I test U.V light + sugars, and sugars + no light.

I really need some advice.
Thanks.

[canalon]

I would say: Up to you:)

Depending on the time and budget that you can dispose of, you can test whatever you want. Why not test the growth rate in all conditions: +/- sugar and +/- light.