The effects of benzoate, cyclohex-1-ene carboxylate, and cyclohexane carboxylate on biotransformation of o-phthalate in sediment slurries under sulfate-reducing conditions

It was found in this study that while addition of the predicted intermediate product benzoate did not, addition of cyclohex-1-ene or cyclohexane carboxylate did inhibit the biotransformation of o -phthalate in sulfate-reducing o -phthalate-adapted sediment slurries under a CO 2 /H 2 atmosphere. Biotransformation rates of benzoate were slightly higher than those of o -phthalate in sediment slurries amended with o -phthalate plus benzoate. By using the most probable number (MPN) method to determine the number of o -phthalate transformers, similar growth dynamics of o -phthalate transformers were observed in sediment slurries amended with or without benzoate. The number of benzoate transformers (1 × 10 9 cells g −1 of sediment) remained the same in sediment slurries repeatedly amended with a mixture of o -phthalate and benzoate after their transformation. o -Phthalate transformers decreased about three orders (1 × 10 9 to 1 × 10 6 cells g −1 of sediment) of magnitude after biotransformation of o -phthalate, and remained at the low number thereafter until re-amendment with o -phthalate. o -Phthalate transformers increased to 1 × 10 8 cells g −1 of sediment just prior to the onset of biotransformation of the o -phthalate.