Problem:

In protocols for minimal media for growing bacteria I often see that a vitamin mix or a mix of various trace metals is added. But at least for E. coli I know that those are not strictly necessary, they also grow in minimal medium without any of this.

Required:

Question 1: Does it make sense to add vitamins or trace elements when growing common E. coli for protein expression like BL21 (DE3) in minimal medium?

Question 2: Is there some literature data on how this can affect the growth of the bacteria? Please explain your answer.