Analysis of bacterial diversity in oysters (Crassostrea gigas) through metagenomics and taxonomic study of a novel bacterial species from seawater

Abstract

Human consumption of oysters is rampant worldwide as they contain a number of nutritional benefits. Oysters are filter feeders and may possess various microorganisms, which can either be beneficial or harmful to health. They are expected to contain almost any microorganism present in the surrounding water, indicating that a large number of bacteria might be obtained by direct filtration. Almost all oyster samples in this study were dominated by Lactococcus, followed by Ewingella americana. Another dominating genus is Leuconostoc. Likewise, the microflora of oysters might depend on the quality of water where they live. With this, it may also be significant to review the bacterial composition of seawater. Using conventional methods, isolation and identification of bacteria were done for a seawater sample. A Gram-negative, rod-shaped bacterium (strain M9T) was isolated from seawater off the coast of Gwangalli Beach in Busan, South Korea. Phylogenetic analysis based on 16S rRNA sequences showed that it has a closest similarity to Microbulbifer salipaludis (strain SM-1T) with a similarity of 97.7%. Herewith, due to phenotypic, phylogenetic and genomic distinctiveness, strain M9T should be represented as a novel species of the genus Microbulbifer, for which the name Microbulbifer gwanganensis sp. nov. is hereby proposed (= KCTC 32461).