Psychrotrophic Hydrocarbon-Oxidizing Bacteria Isolated from Bottom Sediments of Peter the Great Bay, Sea of Japan

Five strains of psychrotrophic hydrocarbon-oxidizing bacteria were isolated from the bottom sediments of Peter the Great Bay of the Sea of Japan. They were classified into the following species: Rhodococcus erythropolis, Rhodococcus sp., Sphingomonas sp., Pseudomonas sp., and Alcanivorax sp. All studied bacteria showed high oxidizing ability in relation to the decomposition of n-alkanes (C9-C27), phytane, pristane, and polycyclic aromatic hydrocarbons at 5 and 22 degrees C. At the same time, the degradation of hydrocarbons was more intense at 5 degrees C. Despite the different taxonomic affiliations of the obtained microorganisms, all strains primarily utilized short- (C9-C13) and long-chain (C21-27) alkanes, as well as polycyclic aromatic hydrocarbons. The highest hydrocarbon-oxidizing activity was shown by the strain Rhodococcus erythropolis AP_291. The latter utilized more than 50% of all hydrocarbons in the model mixture during the first week of the experiment at 5 degrees C.