Marinilabilia nitratireducens sp. nov., a lipolytic bacterium of the family Marinilabiliaceae isolated from marine solar saltern.

A Gram-negative, rod shaped, motile bacterium, was isolated from a marine solar saltern sample collected from Kakinada, India. Strain AK2(T) was determined to be positive for nitrate reduction, catalase, Ala-Phe-Pro-arylamidase, β-galactosidase, β-N-acetylglucosaminidase, β-glucosidase, β-xylosidase, α-glucosidase, α-galactosidase and phosphatase activities, hydrolysis of aesculin, Tween 20/40/60/80 and urea. It was determined to be negative for oxidase, lysine decarboxylase and ornithine decarboxylase activities and could not hydrolyze agar, casein, gelatin and starch. The predominant fatty acids were identified as iso-C(15:0) (28.2 %), anteiso-C(15:0) (23.2 %), iso-C(13:0) (19.9 %) and iso-C(15:0) 3-OH (13.9 %). Strain AK2(T) was found to contain menaquinone with seven isoprene units (MK-7) as the sole respiratory quinone and phosphatidylethanolamine, one unidentified phospholipid and three unidentified lipids as polar lipids. The 16S rRNA gene sequence analysis indicated the strain AK2(T) as a member of the genus Marinilabilia and is closely related to Marinilabilia salmonicolor with pair-wise sequence similarity of 98.2 %. Phylogenetic analysis of 16S rRNA gene revealed that the strain AK2(T) clustered with M. salmonicolor. However, DNA-DNA hybridization with M. salmonicolor JCM 21150(T) showed a relatedness of 48 ± 0.5 % with respect to strain AK2(T). The DNA G+C content of the strain was determined to be 40.2 mol%. Based on the phenotypic characteristics and phylogenetic inference, it is proposed that the strain AK2(T) represents a novel species of the genus Marinilabilia, for which the name Marinilabilia nitratireducens sp. nov. is proposed. The type strain of M. nitratireducens sp. nov. is AK2(T) (= MTCC 11402(T) = JCM 17679(T)).