Extraction and isolation of natural food additives, especially flavors, is sometimes expensive.
Increasing attention is being paid to the origin of food additives, and those with natural origin are preferred by customers.
The process was intensified using a continuous-flow reactor-membrane filtration system (flow 0.1 mL/min, substrate concentration 10 mM, pH 7, 24 ☌) with cell lysate as biocatalyst combined with a cofactor regeneration system, which allowed obtaining > 99% bioconversion of massoia lactone. The biotransformation performed in batch mode, using Ca 2+-alginate immobilized cells of Escherichia coli BL21(DE3)/pET30a-OYE3, furnished the desired product with complete conversion in 30 min. The selected biocatalyst, either in the form of purified enzyme, cell lysate, whole cells or immobilized cells, was tested in the batch system as well as in the packed-bed flow bioreactor. Of 13 different ene-reductases isolated, purified and tested, OYE3 was found to be the most efficient biocatalyst. In this work, enantiomerically pure ( R)-(+)-δ-decalactone was obtained by reduction of the C=C double bond of natural massoia lactone in a continuous-flow reactor. Biotransformation has become an attractive approach to obtain natural products. The demand for natural food flavorings increases every year.