Optimization and scaling up of a biotechnological synthesis of natural green leaf volatiles using Beta vulgaris hydroperoxide lyase

Following a promising preliminary study concerning sugar beet leaves valorization and to fulfill the high demand in natural C-6-aldehydes flavors, an efficient biocatalytic reaction was developed to synthesize (2E)-hexenal at large scale. As major product of the lipoxygenase enzyme, 13-HPOT was converted by sugar beet hydroperoxide lyase extracted from leaves or expressed by recombinant Escherichia coli strains. With the adaptation of a fed-batch substrate addition and a continuous extraction of volatiles, 3.46 mM and 1.37 mM of C-6-aldehydes were produced with the native hydroperoxide lyase at respectively 2 and 100 L scale. Furthermore, higher molar productivity of green leaf volatiles was reached with recombinant hydroperoxide lyase (5.5 mM at 2 L scale) while no others side products from the lipoxygenase pathway were formed. Once purified, these natural aromas are suitable for food and beverage preparations, perfumes or cosmetic products. (C) 2012 Elsevier Ltd. All rights reserved.