1.2.1.68 biotechnology biotransformation of eugenol to ferulic acid by a recombinant strain of Ralstonia eutropha H16. The gene calB, encoding coniferyl aldehyde dehydrogenase, and ehyAB and calA encoding eugenol hydroxylase and coniferyl alcohol dehydrogenase, respectively, are amplified and combined to construct a catabolic gene cassette. This gene cassette is cloned in the broad-host-range vector pBBR1-JO2 and transferred to Ralstonia eutropha H16. A recombinant strain of Ralstonia eutropha H16 harboring this plasmid expresses functionally active eugenol hydroxylase, coniferyl alcohol dehydrogenase, and coniferyl aldehyde dehydrogenase. Cells of Ralstonia eutropha H16 from the late-exponential growth phase are used asa biocatalysts for the biotransformation of eugenol to ferulic acid. A maximum conversion rate of 2.9 mM of eugenol per h per liter of culture is achieved with a yield of 93.8 mol% of ferulic acid from eugenol within 20 h, without further optimization 654264 1.2.1.68 biotechnology highly efficient two-step biotransformation of eugenol to ferulic acid and further conversion to vanillin in recombinant strains of Escherichia coli. Maximum production rate for ferulic acid at large scale is 14.4 mM per h per liter of culture, yield of 93.3% with respect to the added amount of eugenol 654275 1.2.1.68 nutrition production of vanillin 288325