Siansivirga zeaxanthinifaciens gen. nov., sp. nov., a novel zeaxanthin-producing member of the family Flavobacteriaceae isolated from coastal seawater of Taiwan

Abstract

A strictly aerobic, Gram-negative, rod-shaped bacterium (strain CC-SAMT-1(T)) showing gliding motility was isolated from coastal seawater of China Sea, Taiwan. Strain CC-SAMT-1(T) synthesizes all-trans-zeaxanthin (6.5 ± 0.5 mg g(-1) dry biomass) as a predominant xanthophyll carotenoid. As determined by 16S rRNA gene analysis, strain CC-SAMT-1(T) shared very high sequence similarity to the members of the genera Mariniflexile (96.1-95.3%) and Gaetbulibacter (96.0-95.9%); however, it formed a distinct phyletic lineage distantly associated with Mariniflexile species. Polar lipid profile constitutes phosphatidylethanolamine, four unidentified aminolipids, four unidentified lipids, and an unidentified glycolipid. Strain CC-SAMT-1(T) contains excessive unidentified aminolipid lipid (AL2-4) and glycolipid contents, and therefore clearly distinct from Mariniflexile species. Major fatty acids (> 5% of total fatty acids) were iso-C(15:0) (14.8%), iso-C(17:0) 3-OH (11.8%), iso-C(15:1) G (10.6%), anteiso-C(15:0) (9.7%), C(16:0) (8.1%), iso-C(16:0) 3-OH (7.9%), iso-C(15:0) 3-OH (7.5%), and summed feature 3 (containing C(16:1) ω6c and/or C(16:1) ω7c) (7.5%). Menaquinone-6 (MK-6) was major respiratory quinone. DNA G+C content was 33.7 mol%. Based on polyphasic taxonomy, strain CC-SAMT-1(T) represents a novel genus and species in the family Flavobacteriaceae for which the name Siansivirga zeaxanthinifaciens gen. nov., sp. nov. is proposed. The type strain is CC-SAMT-1(T) (= BCRC 80315(T) = JCM 17682(T)).