What factor can increase the yield of GFP when expressed in bacteria?

Using a plasmid with a strong promoter is crucial for increasing the yield of GFP when expressed in bacteria. A strong promoter is a DNA sequence that initiates transcription of the target protein, in this case, GFP. The strength of the promoter directly influences how efficiently RNA polymerase binds and transcribes the DNA into mRNA. Consequently, a strong promoter leads to higher levels of mRNA production, which increases the translation of GFP into protein.

The abundance of the plasmid's promoter drives the expression levels, providing more of the genetic template for ribosomes to translate into the fluorescent protein. This results in a greater overall yield of GFP, making it a key factor in protein expression strategies.

The other options address different aspects of bacterial growth and protein expression but do not contribute as directly to the increase in protein yield as a strong promoter does. Lowering temperature may affect protein folding or solubility, while reducing IPTG concentration can limit the induction of the promoter, and inhibiting bacterial growth may lead to less overall biomass and protein production. Thus, leveraging a strong promoter is the most effective strategy to maximize GFP yield in bacterial systems.