From Brian Cook:
Just poked around the iGEM page. I'll try to update with my notes later after I create my account.
But a few notes & cool ideas:
1) Methyl salicylate is the most soluble of all the odorants you've listed. It's only "slightly" soluble in H20 (<1 mg/mL) but I have some in lab and even at that concentration you get a nice wintergreen scent. I can give you some if you'd like to try for yourself! :)
2) Indole has a MW of 117.15, so getting it over 300 might be a bit of a challenge... but (read on)
3) ...it might be possible to metabolize indole into salicylic acid (thus kill two birds with one stone!). Thus convert the stinky into minty. The pathways are still a bit fuzzy, but we could possibly go through anthranilate as an intermediate. This would require at least 2 more enzyme -- However, I can't seem to find any enzymes for the pathway which have been sequenced yet. But cool idea, yeah? Definitely bears more investigation.
Maybe helpful link: http://www.arabidopsis.org:1555/ARA/NEW-IMAGE?type=PATHWAY&object=PWY-981