Diversity of marine bacteria isolated from early phase of biofilm formation

Abstract

Bacterial biofilms are generally described as surface-associated bacterial communities comprising exopolysaccharide-surrounded microcolonies. Biofilm formation on surfaces has important implications for ecological function and industrial processes. However, there was little information about the bacterial species concerned in the early process of biofilm formation. In the present study, bacteria were isolated from the early phase of biofilm formation and their phylogenetic properties were investigated in order to procure standard bacterial strains for biofilm control studies. Acrylic surfaces were emerged in near shore seawater for 3 days at five areas of the Korean Peninsula. Bacterial isolates were obtained using ZoBell 2216e agar medium. Based on the morphological characteristics, 139 colonies were isolated and partial sequences of 16S rDNA (300 to 500 bps) from 75 of the isolates were analyzed. The sequences showed high similarities to previously reported sequences in GenBank database. The isolates could be assigned to 26 known genera which have been reported widespread in marine environment. Among the analyzed, proportion of each phylogenetic group was as following; 32.0% of -Proteobacteria, 26.7% of -Proteobacteria, 26.7% of Gram positive bacteria and 14.7% of CFB group bacteria. Approximately 35% of the isolates had been reported previously as uncultured or unidentified in GenBank database. Genus Bacillus, Erythrobacter, Pseudoalteromonas and Psychroserpens were detected more than 3 different sampling areas. As any bacterial genus was not detected in all sampling areas, the bacterial composition of early phase biofilm showed high geographical variation.