HYDROCARBON-DEGRADING BACTERIA ASSOCIATED WITH INTESTINAL TRACT OF FISH FROM THE BALTIC SEA

The hydrocarbon-degrading bacterial diversity of the intestinal tract content of fish - the Baltic cod (Gadus morhua), plaice (Platichthys flesus) and the Baltic herring (Clupea harengus) - from the Baltic Sea has been investigated by molecular methods: DNA extraction, amplification polymerase chain reaction product and sequencing of partial 16S rRNA genes. The results of this study show that dense total heterotrophic bacterial populations occur in the intestinal tract of investigated fish. The data obtained showed that the abundance of hydrocarbon-degrading bacteria in the intestinal tract of fish varied from 2.40x10(4) to 1.08x10(5) cfu g(-1) between fish species and was still high. Phenotypic examination of the recorded hydrocarbon-degrading bacteria from the intestinal tract of the Baltic cod, plaice and the Baltic herring revealed that they belong to Aeromonas, Pseudomonas/Shewanella. Molecular species of hydrocarbon-degrading bacteria found in the digestive tract of fish from the Baltic Sea were: Aeromonas veronii, Aeromonas sobria, Shewanella spp. and Acinetobacter spp. We argue that hydrocarbon-degrading bacteria in intestinal tract of fish take part in purification processes, as well as, bacteria in water and play a role in adaptation and survival of fish chronically exposed to pollution with hydrocarbons.