[DIYbio] Re: Student group needs help genetically modifying foods.

For something as simple as Vitamin C biosynthesis in yeast, chances are someone has already tried this. In this case, a simple google search led to this paper:

Biosynthesis of Vitamin C by Yeast Leads to Increased Stress Resistance

in which they show that you only need three genes to produce L-ascorbic acid (vitamin C) in yeast, although they eventually added two more to avoid a bottleneck in the tail end of the pathway.

Engineering five genes into yeast from scratch is still beyond what can be done with a highschool team (and Vitamin E looks even harder). Luckily for you, the 2011 Johns Hopkins iGEM team already made a plasmid with the three key enzymes, although I'm not sure they got it to work:

http://2011.igem.org/Team:Johns_Hopkins/Project/VitC

Instead of Vitamin C or E, you could focus on Vitamin A (aka beta-carotene) instead. The same Johns Hopkins team also made a 3-gene plasmid for Vitamin A biosynthesis, and demonstrated that it worked in yeast (and baked a bread with it!):

http://2011.igem.org/Team:Johns_Hopkins/Project/VitA
http://2011.igem.org/Team:Johns_Hopkins/Vit/Results

You (or one of your teachers) may be able to get the plasmid from this group. At that point, it would simply be a matter of transforming it into yeast, and testing it out - something that should be well within reach of a high school team. If you get that done, you can thenn modify the pathway further to produce any of a range of other brightly colored carotenoids, such as zeaxanthin or canthaxanthin.

Patrik