Phylogeny and structural insights of lipase from Halopseudomonas maritima sp. nov., isolated from sea sand

A Gram-negative, aerobic bacterial strain RR6 T was isolated from the sea sand to produce lipase and proposed as a novel species of Halopseudomonas . The optimum growth occurred at 28–37 °C, and the pH was 6.0–8.0. The optimum growth occurred at 3.0 -6.5% (w/v) NaCl. The major cellular fatty acids were C10:0 3OH, C12:0, C16:1 ω 7c/16:1 ω 6c, 18:1 ω 7c and/or 18:1 ω 6c, and C16:0. The predominant polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, unidentified phospholipid, and unidentified lipids. The genome is 3.93 Mb, and the G + C content is 61.3%. The 16S rRNA gene sequences shared 99.73–99.87% sequence similarity with the closely related type strains of Halopseudomonas . The average nucleotide identity and average amino acid identity of strain RR6 T with reference type strains were below 95–96%, and the corresponding in-silico DNA–DNA hybridization values were below 70%. Strain RR6 T clustered with Halopseudomonas gallaeciensis V113 T and Halopseudomonas pachastrellae CCUG 46540 T in the phylogenetic tree. Further, lipase produced by this bacterium belongs to α/β hydrolase lipase family and exhibits structural similarity to the lactonizing lipase. Based on the polyphasic analysis, the new isolates RR6 T represent a novel species of Halopseudomonas for which Halopseudomonas maritima sp. nov. is proposed. The type strain is RR6 T (= NBRC 115418 T = TBRC 15628 T ).