The reason why I ask is because I want to add sorbitol to be terrific broth with glycerol but I'm worried it will preferentially metabolize the sorbitol. I want to add sorbitol because I've read it will help reduce inclusion bodies which is a problem for my protein. I cant use urea or other harsh denaturants.
Since its a relatively inexpensive experiment, I'd simply test the sorbitol. In my experience lower temps (down to 15-20C) have a much better chance of decreasing IB formation. To that end I've had great luck with Studier's autoinduction media at RT. Good luck!!
I think E. coli is likely to use both glycerol and sorbitol equally well. However I think the problem isn't whether they will metabolize sorbitol, but rather whether they will metabolize all of it. You can just add more. If you think about it, if you had 10ug/ml glycerol plus 10ug/ml sorbitol in your medium, the amount of carbon source would be the same as having 20ug/ml sorbitol.
Having said that, I tend to agree with Edward Michelini that I think changing other conditions is more likely to reduce inclusion body formation, especially slowing down the growth rate which can be done at lower temperatures.
If you're using IPTG, using as low a concentration as possible can often help too, IPTG is a very strong inducer and having it in excess can result in the expressed protein being insoluble. +1 with Edward Michelini on the reduced temp, that can have a considerable effect on solubility.
I normally, ran a matrix of test expressions (0.1, 0.5 and 1 mM ITPG and 18, 25 and 37'C), so 9 conditions to see which gave the best expression results.
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