R. Takeuchi et al., Anaerobic transformation of chlorophenols in methanogenic sludge unexposedto chlorophenols, CHEMOSPHERE, 41(9), 2000, pp. 1457-1462
Transformation of all 19 chlorophenol (CP) isomers was investigated in a la
boratory anaerobic methanogenic sludge that had not been exposed to synthet
ic chemicals. Concentration of CP was analyzed over time to calculate disap
pearance rate constants using first-order reaction kinetics and all possibl
e CP degradation pathways were estimated. The rate constants ranged between
0.46 x 10(-3) and 0.161 day(-1). CPs were transformed via dechlorination.
The chlorine atom at the ortho-position was the most easily dechlorinated,
whereas dechlorination rate at the para-position was lowest. The overall pa
thways of CP transformation were much less diverse than that we previously
found for contaminated sediment. The Dolfing hypothesis of microbial select
ion of the most thermodynamically favorable pathways was not applicable for
CP transformation in this study as well as previous study performed by our
group. (C) 2000 Elsevier Science Ltd. All rights reserved.