(a) Kinetics of reductive dechlorination of 2,3-dichloro (DCDD)- to 2-monochlorodibenzo-p-dioxin (MCDD) by strain CBDB1. Two 3 ml cultures were completely extracted for the analyses of chlorinated dibenzo-p-dioxins at each time-point shown. Quantitative transcription analysis of the four rdhA genes cbrA (filled triangles), cbdbA1624 (filled circles), cbdbA1453 (filled inverted triangles) and cbdbA1588 (filled squares) of strain CBDB1 in the presence of 2,3-DCDD (b), and (c) in the control not supplemented with an electron acceptor is shown. Mean values from duplicate cultures and s.d. are shown.