Vitamins made by GMOs?

At NPR's blog The Salt, Dan Charles has some interesting discussion on the change in the nutritional profile for Cheerios after they went "non-GMO." 

Remember when Cheerios and Grape-Nuts went GMO-free? That was about a year ago, when their corporate creators announced that these products would no longer contain ingredients made from genetically modified organisms like common types of corn, soybeans or sugar beets.

When they actually arrived on supermarket shelves, though, there was a mysterious change in their list of ingredients. Four vitamins that previously had been added to Grape-Nuts — vitamins A, D, B-12 and B-2 (also known as riboflavin) — were gone. Riboflavin vanished from Cheerios.

Charles speculates on what caused the change.  One possibility is that some vitamins these days are apparently produced with genetically modified bacteria and yeast.  These microbes can reproduce quickly, and as a result they can efficiently produce vitamin B-12 or riboflavin, if they've got the right genes.  It's a fascinating process that holds much promise in other applications as well.   

Charles ends with what may be an interesting irony for companies who go GMO and maintain the same vitamin content:

That leaves one method of vitamin production that’s cheap, industrial-scale, and reliably non-GMO: synthetic chemistry. Vitamins are commonly manufactured from scratch in chemical factories, using ingredients that cannot be linked to any genes or biological process at all. That technology may not inspire great affection, but it does, at least, qualify as non-GMO.