Biotransformations in the Flavour Industry

Abstract

Bacteria and fungi synthesise or degrade a vast number of natural and xenobiotic substrates. Biotransformations and bioconversions occur, if a single substrate structure is altered by an identifiable redox, hydrolysis, or addition type reaction, or by a sequence of these reactions. Generally competing with chemosynthesis, biocatalysts possess inherent advantages: They functionalise chemically inert carbons, modify one functionality in a multifunctional molecule selectively or specifically, introduce chirality, resolve racemates, and operate under ambient conditions. The production of natural flavour and aroma ingredients could benefit from these characteristics. The biotransformation of volatile terpenes particularly well demonstrates perspectives, but also current problems. Solvent tolerant bacteria hold much promise for a lipophilic biotechnology. Genetic engineering will help to create tailor-made biocatalysts. Downstreaming of products, based on in situ solvent extraction or adsorption, is required for an efficient bioprocess. Cost calculations show that high-yielding biotransformations have commercial potential.