FIG. 6.

Reuse of cells. The graph shows hydromorphone yields obtained from consecutive incubations of recombinant E. coli JM109 with 20 mM morphine. Biotransformations were carried out as described in the text. Cells were harvested once the biotransformation had reached completion (12 to 22 h) and washed with 50 mM Tris-HCl (pH 8.0) prior to the start of the next biotransformation. Figures shown are the averages of duplicate measurements, and error bars represent the standard deviations.