Pontibacter cellulosilyticus sp. nov., a carboxymethyl cellulose-hydrolysing bacterium isolated from coastal water

Abstract

A Gram-stain-negative, rod-shaped, non-motile, red-pink bacterium designated SD6T was isolated from coastal marine water at Sadong Beach, Ulleung Island, South Korea. Cells of SD6T grew at 10–42 °C (optimum, 30 °C), pH 5.0–9.0 (optimum, pH 6.0–7.0) and at 0–8.0 % (w/v) NaCl (optimum, 0–3 %). Moreover, 16S rRNA gene sequence analysis indicated that strain SD6T was a member of the genus Pontibacter , sharing similarities to Pontibacter aydingkolensis XAAS-1T (98.0 %), Pontibacter amylolyticus 9-2T (97.3 %), Pontibacter korlensis X14-1T (97.2 %) and Pontibacter soli HYL7-26T (96.8 %). The predominant fatty acids of strain SD6T were identified as iso-C15 : 0 and summed feature 4 (comprising anteiso-C17 : 1 B and/or iso-C17 : 1 I) and the sole respiratory quinone was identified as MK-7 (menaquinone 7). Major polar lipids included phosphatidylethanolamine, one unidentified phosphoglycolipid, two unidentified glycolipids and one unidentified lipid. The average nucleotide identity and in silico DNA–DNA hybridization values of strain SD6T with its closely related strains were 72.8–79.8 % and 19.2–22.6 %, respectively. The genomic DNA G+C content was 45.4 mol%. In accordance with the results of phenotypic, chemotaxonomic and phylogenetic data, strain SD6T represents a novel species of the genus Pontibacte r, for which the name Pontibacter cellulosilyticus sp. nov. is proposed. The type strain is SD6T (=KACC 21543T=NBRC 114313T=JCM 31022T).