Biotechnology of terpenes and flavors/fragrances

Terpenes (aka "Isoprenoids") include a fascinating multitude of bioactives. Many of them have a huge potential, e.g. as flavor and fragrances, pigments, vitamins, antioxidants, preservatives for food or cosmetics or pharmaceutical agents.

Terpenes prevail in organisms of all kingdoms. For their biosynthesis first (mostly) chiral hydrocarbon units are built according to a uniform principle. These are then converted to various metabolic products by specific secondary transformations.

It is obvious to rely on the selectivity of enzymatic reactions for the technical production of these complex structures. Chemical synthesis is often too unspecific and complicated structures can only be realized by elaborate processes, if at all.

Similar applies to the production of aroma chemicals in general. Here too, enzymes surpass chemical catalysts in regio- and stereoselective functionalisation of the respective aroma precursors. Biotechnological products that are generated from natural raw materials are "natural" flavor compounds and thus have the added benefit of higher demand in the food sector than their chemically synthesized counterparts.

Many of the interesting products trace back to terpene structures such as (+)-limonene, α -pinene or 3-carene, which can be found in large amounts in nature and thus are abundantly available chiral starting materials. For the biotransformation of terpenes several biological and process engineering questions have to be addressed first. The addition of the hydrophic and cytotoxic terpenes to the biological reaction system for example, the removal of inhibiting products from the bioprocess or the optimization of the catalytic performance of enzymes and microorganisms by molecular biology. Finally, metabolic engineering plays an important role if the biosynthesis of terpenes and flavors/frangrances in microorganisms shall be addressed for an optimized de novo production of components.