Catenovulum algicola sp. nov., an agar-hydrolysing, halophilic gammaproteobacterium isolated from kelp seedlings

A pale white, Gram-stain-negative, strictly aerobic, halophilic, agar-hydrolysing and rod-shaped bacterium, designated strain 2E275 T , was isolated from kelp seedlings at Weihai, China. The cells are motile by means of a single polar flagellum. The isolate had an absolute requirement for agar and formed a depression when grown on Marine Agar 2216 plates for 3 days. Strain 2E275 T growth occurred at 4–42°C (optimum, 37°C), with 0–12% (w/v) NaCl (optimum, 3%), and at pH 5.5–10.5 (optimum, pH 6.5-7.0). The isolate could not be cultured in MB, but when 0.2% agar was added, they grew well. According to the phylogenetic analysis of the 16S rRNA gene sequence, strain 2E275 T showed the highest sequence similarity of 96.0% with Catenovulum agarivorans YM01 T , followed by Catenovulum sediminis D2 T (94.1%) and Catenovulum maritimum Q1 T (93.7%) . Strain 2E275 T could remarkably hydrolyse agar, cellulose, starch, sodium alginate, casein and Tweens 20, 60, 80, but not DNA and Tween 40. The major polar lipids of strains 2E275 T were phosphatidylglycerol, phosphatidylethanolamine and phosphoaminolipid. The major cellular fatty acids were summed feature 3 (C 16:1 ω 7 c and/or C 16:1 ω 6 c ), summed feature 8 (C 18:1 ω 7 c ) and C 16:0 . Ubiquinone 8 (Q-8) was found to be the major respiratory quinone. The DNA G+C content was 38.2%. On the basis of the phenotypic, genetic and physiological characteristics, strain 2E275 T should be classified as a novel species of the genus Catenovulum , for which the name Catenovulum algicola sp. nov. is proposed. The type strain is 2E275 T (MCCC 1H00528 T = KCTC 92643 T ).