Enhanced bioproduction of 2-phenylethanol in a biphasic system with rapeseed oil

Increasing demand for natural fragrance ingredients and products has led to their global market growth. 2-Phenylethanol (2-PE) is a volatile substance widely used in food and cosmetics manufacturing. It is generally known that yeast can metabolize L-phenylalanine (L-Phe) to produce 2-PE. However, because the product exhibits an inhibitory effect on yeast cells, simple batch cultivation is uneconomic. The aim of this study was to enhance 2-PE productivity using in situ product removal. Here we present a new method of 2-PE production by yeast in a biphasic system with rapeseed oil as the second phase. The chosen solvent is safe, inexpensive and suitable for the extraction of 2-PE. In addition, rapeseed oil appeared to be a valuable source of intermediates for 2-PE synthesis as its presence in the yeast culture significantly enhanced productivity. The process is an environmentally friendly route and gives two final products that can be considered natural: rapeseed oil with a rose odor and pure 2-PE. Both may be subsequently used as food or cosmetics additives. The results obtained are competitive with previously reported values, as it was possible to enhance the overall concentration of 2-PE by 2.7-fold. The total 2-PE concentration in the biphasic system in the 4.5-L biofermentor used was increased to 9.79 g/L, while the 2-PE concentration in the organic phase attained a value of 18.50 g/L.