Flavobacterium nitratireducens sp. nov., an amylolytic bacterium of the family Flavobacteriaceae isolated from coastal surface seawater

Abstract

A novel Gram-negative, rod-shaped, non-motile bacterium, designated strain N1T, was isolated from a marine water sample collected from the sea shore, Bay of Bengal, Visakhapatnam, India. The strain was positive for starch hydrolysis, nitrate reduction and ornithine decarboxylase activities and negative for citrate utilization, urease, oxidase, catalase and DNase activities. The predominant fatty acids were C16 : 0 3-OH, iso-C15 : 0, iso-C15 : 0 3-OH, iso-C17 : 0 3-OH, anteiso-C15 : 0, C16 : 0, C15 : 0 3-OH, and C16 : 1ω7c and/or iso-C15 : 0 2-OH (summed feature 3). Strain N1T contained menaquinone 6 (MK-6) as the sole respiratory quinone. The only polyamine was homospermidine and the major polar lipids were phosphatidylethanolamine (PE), three unidentified aminolipids (AL1–AL3) and two unidentified lipids (L1, L2). The DNA G+C content of the strain was 36.3 mol%. 16S rRNA gene sequence analysis indicated that strain N1T was a member of the genus Flavobacterium and closely related to Flavobacterium resistens with pairwise sequence similarity of 96.5 %. Phylogenetic analysis showed that strain N1T clustered with Flavobacterium glycines and Flavobacterium daejeonense with a distance of 4.8 and 6.0 % (95.2 and 94.0 % similarity), respectively. Based on the phenotypic characteristics and on phylogenetic inference, strain N1T represents a novel species of the genus Flavobacterium , for which the name Flavobacterium nitratireducens sp. nov. is proposed. The type strain is N1T ( = MTCC 11155T = JCM 17678T).