FIG. 1.

Formation of yellow meta ring cleavage products from diphenylmethane and dibenzofuran by E. coli expressing chimeric biphenyl dioxygenases. The cells were incubated with 0.1 mM substrate at 30°C for 1 h. The formation of yellow compounds was measured at the corresponding absorption maximum. The degradation activities of KF707 Bph Dox and LB400 Bph Dox were used as the basal activities (set to 100) toward diphenylmethane and dibenzofuran, respectively. The activity of KF707 Bph Dox is shown by the larger square on the x axis, and that of LB400 Bph Dox is shown by the larger triangle on the y axis. The closed circles indicate the activities in E. coli expressing the evolved Bph Dox. The relative degradation activities of 80 clones were plotted for the basal activities.