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 Pontibacter, for which the name Pontibacter cellulosilyticus sp. nov. is proposed. The type strain is SD6T (=KACC 21543T=NBRC 114313T=JCM 31022T).