Analytical scale enantioselective biocatalytic C-H fluorination. The suspension of E. coli cells expressing ACCO in M9-N buffer (typically OD600 = 10-30, 540 μL) was added to a vial (2 mL) and kept on ice. This vial was then transferred into an anaerobic chamber, where the solution of Mohr's salt (30 μL, 13.3 mM stock solution in degassed H2O) and the N-fluoroamide substrate (30 μL, 133 mM stock solution in MeCN) was added. The final reaction volume was 600 μL; the final concentration of the N-fluoroamide substrate was 6.67 mM. (Note: the reaction performed with E. coli cells resuspended to OD600 = 30 indicates that 540 μL cell suspension with an OD600 of 30 were added.) The vials were sealed and shaken on a Corning digital microplate shaker at room temperature and 680 rpm for 24 h. The reaction mixture was then analyzed by chiral HPLC.