Shewanella septentrionalis sp. nov. and Shewanella holmiensis sp. nov., isolated from Baltic Sea water and sediments

Abstract

Two bacterial strains, SP1W3T and SP1S2-7T, were isolated from samples of water and sediments collected in Vaxholm, a town located on the Stockholm archipelago in the Baltic Sea, in November 2021. The strains were identified as novel genomic species within the genus Shewanella , based upon comparative analysis of whole genome sequence data. Strain SP1W3T (genome size, 5.20 Mbp; G+C content, 46.0 mol%), isolated from water, was determined to be most closely related to S. hafniensis ATCC-BAA 1207T and S. baltica NCTC 10735T, with digital DNA–DNA hybridization (dDDH) values of 61.7% and 60.4 %, respectively. Strain SP1S2-7T (genome size, 4.26 Mbp; G+C content, 41.5 mol%), isolated from sediments, was observed to be most closely related to S. aestuarii JCM17801T, with a pairwise dDDH value of 33.8 %. Polyphasic analyses of physiological and phenotypic characteristics, in addition to genomic analyses, confirmed that each of these two strains represent distinct, novel species within the genus Shewanella , for which the names Shewanella septentrionalis sp. nov. (type strain SP1W3T=CCUG 76164T=CECT 30651T) and Shewanella holmiensis sp. nov. (type strain SP1S2-7T=CCUG 76165T=CECT 30652T) are proposed.