The diversity of culturable organotrophic bacteria from local solar salterns

Abstract

We isolated and cultured bacteria inhabiting solar saltern ponds in Taean-Gun, Chungnam Province, Korea. All of the isolated 64 strains were found to be moderately halophilic bacteria, growing in a salt range of 2-20 %, with an optimal concentration of 5% salt. Bacterial diversity among the isolated halophiles was evaluated via RFLP analyses of PCR-amplified 16S rDNAs, followed by phylogenetic analysis of the partial 16S rDNA sequences. The combination of restriction enzyme digestions with HaeIII, CfoI, MspI and RsaI generated 54 distinct patterns. A neighbor-joining tree of the partial 16S rDNA sequences resulted in the division of the 64 strains into 2 major groups, 45 strains of gamma-Proteobacteria (70.3%) and 19 strains of Firmicutes (29.7%). The alpha-Proteobacteria and Cytophaga-Flavobacterium-Bacterioides groups, which were repeatedly found to exist in thalassohaline environments, were not represented in our isolates. The gamma-Proteobacteria group consisted of several subgroups of the Vibrionaceae (37.5%), Pseudoalteromonadaceae (10.9%), Halomonadaceae (7.8%), Alteromonadaceae (7.8%), and Idiomarinaceae (6.3%). Members of Salinivibrio costicola (29.7%) were the most predominant species among all of the isolates, followed by Halobacillus treperi (12.5%). Additionally, three new species candidates were found, based on similarities of the 16S rDNA sequences to those of previously published species.