A new approach was studied for bio-based production of methyl propionate, a precursor of methyl methacrylate. Recombinant E. coli cells were used to perform a cascade reaction in which 2-butanol is reduced to butanone using alcohol dehydrogenase, and butanone is oxidized to methyl propionate and ethyl acetate using a Baeyer-Villiger monooxygenase (BVMO). Product was removed by in situ stripping. The conversion was in line with a model comprising product formation and stripping kinetics. The maximum conversion rates were 1.14?g-butanone/(L?h), 0.11?g-ethyl acetate/(L?h), and 0.09?g-methyl propionate/(L?h). The enzyme regioselectivity towards methyl propionate was 43% of total ester. Starting from biomass-based production of 2-butanol, full-scale ester production with conventional product purification was calculated to be competitive with petrochemical production if the monooxygenase activity and regioselectivity are enhanced, and the costs of bio-based 2-butanol are minimized.,Copyright ? 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.