Bacterioflora of molluscs in vitro.

The abundance, composition and hydrocarbon-degrading bacteria, as possible biomarkers of contamination with oil hydrocarbons, of autochthonous and alochtonous bacterioflora of the digestive system of bivalve molluscs Anodonta cygnea (A) and Unio tumidus (U) were estimated. For microbiological examination molluscs were collected in Lithuanian rivers: Avandelta, Atmata and Aklas Stream. Bacterioflora of the digestive system of molluscs was investigated by the methods of attenuation and inoculation on agar mediums. The abundance values of heterotrophic, proteolitic and amilotic bacteria of functional groups in the digestive system of bivalve molluscs A. cygnea and U tunidus in individuals of different species and in investigated rivers were variable. The highest amount of heterotrophic and amylolytic bacteria was determined in U tumidus from Atmata river and A. cygnea from the Aklas Stream. The high amounts of hydrocarbon-degrading and conform group bacteria in molluscs from Atmata and Aklas Stream rivers showed possible contamination of water by petroleum, its products and effluent. It was established that abundance of hydocarbon-degrading bacteria in molluscs ranged from 0.9 % to 64.3 %.. Further, the highest prevalence of coliform bacteria (from 1.2% to 4.3%) was registered in digestive system of molluscs A. cygnea and U. tumidus from Atmata and Aklas Stream rivers.