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 SD6(T) was isolated from coastal marine water at Sadong Beach, Ulleung Island, South Korea. Cells of SD6(T) grew at 10-42 degrees C (optimum, 30 degrees 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 SD6(T) was a member of the genus Pontibacter, sharing similarities to Pontibacter aydingkolensis XAAS-1(T) (98.0 %), Pontibacter amylolyticus 9-2(T) (97.3 %), Pontibacter korlensis X14-1(T) (97.2 %) and Pontibacter soli HYL7-26(T) (96.8 %). The predominant fatty acids of strain SD6(T) were identified as iso-C-15:0 and summed feature 4 (comprising anteiso-C-17:1 B and/or iso-C-17:1 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 SD6(T) 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 SD6(T) (=KACC 21543(T)=NBRC 114313(T)=JCM 31022(T)).