Natural indole is produced by plants as a released volatile, and can be found in, for instance, jasmine and neroli essential oils. In maize, indole was shown to be an essential herbivore-induced volatile priming signal. Some bacteria are able to produce small amounts of indole. Indole acts as an extracellular signal molecule, influencing various aspects of bacterial physiology.

Indole is an important flavouring compound with the main market in dairy, tea drinks and fine fragrances and a market size of 30 million €/year. Pure indole, at low concentrations, exhibits a floral odour characteristic of jasmine teas. Currently, indole is mainly produced from coal tar. It can be synthesized by a variety of multi-step chemical conversions.

Currently, natural indole is prepared by conversion of natural L-Trp, which is a costly procedure. There is a strong demand for a more cost-efficient method for preparing natural indole, avoiding chemistry and with improved sustainability.

Our aim is to produce natural indole via microbial fermentation and enzymatic bioconversion.