engleski

Biphenyl-degrading microbial communities as potential catalysts for aerobic degradation of polychlorinated biphenyls (PCBs) in marine environment

The main objective of this work was to screen PCB degradation potential of marine sediment bacteria. A microcosm approach was employed to enriched bacterial communities from different marine sediments collected in urban areas along the Croatian Adriatic coast (vicinity of Rijeka, Zadar and Dubrovnik). Enrichment experiments were performed in sea water diluted with mineral salt medium (SM medium) and supplemented with biphenyl. After only one subculturing it was evident that all enriched communities demonstrated the capability to use biphenyl as a sole carbon and energy source. This suggested that biphenyl-metabolizing bacteria are widespread in coastal marine sediments which often represent the ultimate sink for PCBs and where the levels of concern are often found. The enriched cultures were three to five member communities, with one to two members that were capable to grow on biphenyl. Potential PCB degradation activity of all enriched biphenyl-degrading communities was further screened in batch culture experiments using SM medium with the addition of commercial PCB mixture containing 50% chlorine and congeners with two- to heptachlorobiphenyl. GC analysis of extracted cultures suggested that, although differing in their capabilities, all enriched communities were efficient in the degradation of lower chlorinated congeners (di-, tri- and tetrachlorobiphenyls), while some of them also degraded penta- and hexachlorobiphenyls.

biphenyl; polychlorinated biphenyls; marine sediment bacteria

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