Fig. 2
Biotransformation of styrene by the wild type and the mutations. The whole cell biotransformation with the recombinant cells of BL21/pET-28a-styAB-fdh and its variants were carried out in 50 mL flasks with 10 mL of the KP buffer (200 mM, pH 8.0) containing 26 mM of substrate styrene and 1.0 g cell (dry cell weight) with addition of 50% (v/v) hexadecane at 30 °C and 220 rpm on a rotatory shaker for 15 min. The organic phases were combined, dried with anhydrous sodium sulfate, and subjected to the reverse phase HPLC analysis on a Luna C18 column (flow rate: 0.8 mL/min, methanol–water mixture at a ratio of 75:25). Activities were normalized as percentages of the activity of the wild type. 100% corresponds to an initial activity of 72 ± 10 U/g CDW. The variant of A depicts mutation of V53G/S189I/D305V derived by site-directed mutagenesis of the epPCR library. The mutation of V53G, S189I and D305V were derived by site-directed mutagenesis. All assays were performed in triplicate and the standard deviations of the biological replicates are represented by error bars