A novel bacterium that utilizes monochlorobiphenyls and 4-chlorobenzoate as growth substrates

A bacterial isolate, tentatively named SK-3, was isolated from tertiary lagoon sludge contaminated with polychlorinated biphenyls for over 25 years. SK-3 was able to grow on 2-chlorobiphenyl, 3-chlorobiphenyl, 4-chlorobiphenyl (4-CB), chloroacetate and 4-chlorobenzoic acid (4-CBA) as sole carbon and energy sources. During growth on 4-CB, a stoichiometric amount of chloride ion was produced and growth yields were comparable to those observed during growth on biphenyl. The production of 4-CBA as a metabolite was not observed. Protein yields during growth on 4-CB and biphenyl suggested that the presence of the chlorine did not impede use of carbons on both aromatic rings. Growth on 4-CBA also resulted in nearly stoichiometric production of chloride ion. Benzoate-grown SK-3 was also able to degrade several Aroclor 1242 congeners without the need for a primary substrate of previous growth on biphenyl.