Fermentative Production of Volatile Metabolites Using Brettanomyces bruxellensis from Fruit and Vegetable By-Products

Natural sources of flavour and aroma compounds are highly sought by the modern consumer; however, traditional sources are often low-yielding, and global supply is often outstripped by consumer demand. Fermentation is a favourable route by which natural flavours and fragrances can be produced. A non-Saccharomyces yeast, Brettanomyces bruxellensis, was investigated for its fermentative potential for the production of flavour and aroma metabolites from juice industry by-products: apple pomace, carrot pomace, and orange pomace. Submerged solid-substrate fermentations were carried out using sterile by-products without nutrient supplementation. Gas chromatography-mass spectrometry was used for volatile metabolite profiling of fermented substrates. One compound of interest, phenylethyl alcohol (rose fragrance), was extracted and quantified using GC-MS at a yield of 2.68 g/kg wet carrot pomace weight. This represents a novel, natural production strategy for phenylethyl alcohol compared to the traditional steam distillation of Rosa domascus sp. petals.