Additional file 4. Influence of an energy source on conversion of coniferyl alcohol 2 by E. coli cells. 10 ml E. coli C41(DE3) pCDF-Duet resuspended in reaction buffer (70 g l−1 cww) were supplemented with 1 mM coniferyl alcohol 2. Optionally, 25 g l−1 glycerol or 20 g l−1 D-glucose was added. The reaction was carried out for 24 h at 25 °C, 140 rpm. [2] = coniferyl alcohol 2, [6] = coniferyl aldehyde 6, [IS] = internal standard FSME, * = unspecific peak; chromatograms are shifted vertically