A NEW FACULTATIVE ANAEROBE CAPABLE OF GROWTH ON CHLOROBIPHENYLS

Abstract

Strain B-206 is a new facultative anaerobe, non flagellated, gram negative rod, able to grow on 4-chlorobiphenyl (4CB) and to degrade it. When this strain was grown on 4CB as sole growth substrate, two types of cultures were obtained; either the culture became pink or yellow with the formation of a black pigment. The cultures turning yellow were the more active ones and they were obtained with a large inoculum size or low oxygen tension. 4-Chlorobenzoic acid (4CBA) was detected in both pink and yellow cultures but in much higher concentration in yellow cultures. This compound appeared to be the ultimate metabolite of 4CB in both types of growth since strain B-206 could not grow or degrade 4CBA and that the concentration of 4CBA did not decrease even after the appearance of the yellow compounds. The presence of 4CBA and yellow compounds that differs spectrophotometrically at acid and basic pHs suggest that 4CB is degraded via a meta cleavage between the 1 and 2 position. The absence of any other metabolites than a pink pigment and 4CBA in the pink cultures provides no evidence that in this type of culture there would be some other mechanism of cleavage of the biphenyl molecule. In the yellow culture type, there was also formation of a black pigment. This pigment, like the pink compound, possessed all the characteristics of the phenolic type pigments. Strain B-206 could also grow on biphenyl, 3-chlorobiphenyl, 2-chlorobiphenyl, benzoic acid but it was unable to grow on any of the monochlorinated benzoic acids. Although this strain could not grow on Aroclor 1254, we have evidence that it is partially transformed by this strain.