Alteromonas arenosi sp. nov., a novel bioflocculant-producing bacterium, isolated from intertidal sand

A novel Gram-stain-negative, strictly aerobic and bioflocculant-producing bacterium, designated as ASW11-36^T, was isolated from an intertidal sand collected from coastal areas of Qingdao, PR China. Growth occurred at 15-40 °C (optimum, 30 °C), pH 7.0-9.0 (optimum, pH 7.5) and with 1.5-7.0% (w/v) NaCl (optimum, 2.5-3.0%). In the whole-cell fatty acid pattern prevailed C_16:0 and summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c). The major isoprenoid quinone was determined to be Q-8 and the major polar lipids were phosphatidylethanolamine (PE) and phosphatidylglycerol (PG), one unidentified aminolipid (AL), one unidentified glycolipid (GL), and two lipids (L1, L2). Based on the phylogenetic analyses of 16S rRNA gene sequences and 618 single-copy orthologous clusters, strain ASW11-36^T could represent a novel member of the genus Alteromonas and was closely related to Alteromonas flava P0211^T (98.4%) and Alteromonas facilis P0213^T (98.3%). The pairwise average nucleotide identity and digital DNA-DNA hybridization values of the ASW11-36^T genome assembly against the closely related species genomes were 71.8% and 21.7%, respectively, that clearly lower than the proposed thresholds for species. Based on phenotypic, phylogenetic, and chemotaxonomic analyses, strain ASW11-36^T is considered to represent a novel species of the genus Alteromonas, for which the name Alteromonas arenosi sp. nov. is proposed. The type strain is ASW11-36^T (= KCTC 82496^T = MCCC 1K05585^T). In addition, the strain yielded 65% of flocculating efficiency in kaolin suspension with CaCl₂ addition. The draft genome of ASW11-36^T shared abundant putative CAZy family related genes, especially involved in the biosynthesis of exopolysaccharides, implying its potential environmental and biological applications.