Efficient whole-cell oxidation of α,β-unsaturated alcohols to α,β-unsaturated aldehydes through the cascade biocatalysis of alcohol dehydrogenase, NADPH oxidase and hemoglobin

Table 1 Selective oxidation of 3-methyl-2-buten-1-ol to 3-methyl-2-butenal catalyzed by cells expressing YsADH, TkNOX and/or VsHGB

The protein(s) expressed in E. coli cells	Yield of 3-methyl-2-butenal (%)^a
YsADH	11.75 ± 0.22
YsADH and TkNOX	21.3 ± 0.79
YsADH, TkNOX and VsHGB	35.48 ± 1.47
YsADH, TkNOX and VsHGB^b	51.3 ± 2.03

The reaction mixture (5 ml) contained 100 mM 3-methyl-2-buten-1-ol, 0.3 g lyophilized cells, 0.4 mM NADP⁺, 0.2 mM FAD, and 50 mM Tris-HCl (pH 8.0). The reaction was carried out at 45 °C and 600 rpm for 2 h. The values are presented as the standard deviation from triplicate measurements
^aThe yield of 3-methyl-2-butenal was calculated with the following equation: yield (%) = product formed (mM)/(product formed (mM) + substrate remaining (mM)) × 100%
^bThe atmosphere of the reactor was replaced with pure oxygen

ISSN: 1475-2859