Fig. 4

The comparison of isoprene production by 50 ml in vitro and in vivo systems. The concentration of MVK (0.5 µM) was similar in both in vitro (black) and in vivo (red) systems. The cell free in vitro system has 1 synthetic unit (0.5 µM of MVK, PMK, MVD; 1.0 µM of IDI, 8.0 µM of ISPS) with 50 mM phosphate buffer, 30 mM potassium chloride, 10 mM magnesium chloride, and 4 mM β-mercaptoethanol. 50 ml culture of engineered E. coli (BL21(DE3)/pYJM14/pACY-ISPS, Table 1) which expressed the five enzymes of the lower MVA pathway was utilized as the in vivo control. Both systems was initiated by addition of 2.5 mM mevalonic acid and incubated at 30 °C in rotary shaker (180 rpm). Samples were taken to analyze their isoprene production at different time points. The data shown are means of three repeated experiments and the error bars present the standard deviation