http://www.synbioproject.tech/cpi/applications/vanillin/
Vanilla and vanillin are together among the most important fragrance and flavouring products in the world, with the total market worth approximately USD 600 million (and a total volume of approx. 18,000 tonnes). Only a small fraction of this volume consists of natural vanilla, with the vast majority being synthetic vanillin. The most important applications are in confectionery and dairy products. Vanillin is also used in the fragrance industry, for example in perfumes and cleaning products, as well as to mask unpleasant tastes in medicines, and in livestock fodder. Source
Genetically modified yeast fermentation.