Marinobacter lipolyticus sp. nov., a novel moderate halophile with lipolytic activity S. Martı ´n, M. C. Ma ´ rquez, C. Sa ´ nchez-Porro, E. Mellado, D. R. Arahal and A. Ventosa Correspondence A. Ventosa ventosa@us.es Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, 41012 Sevilla, Spain In the course of a screening programme in hypersaline habitats of southern Spain to isolate halophilic bacteria that are able to produce different extracellular enzymes, a novel, moderately halophilic bacterium (strain SM19 T ) that displays lipolytic activity has been isolated and characterized. Strain SM19 T is a Gram-negative rod that grows optimally in culture media that contain 7?5 % NaCl. The DNA G+C content was 57?0 mol%. According to phenotypic and genotypic data, this strain was assigned to the genus Marinobacter. However, 16S rDNA sequence similarity between strain SM19 T and species of the genus Marinobacter was <96?7 %; this value is sufficiently low to propose its designation as a novel species. In addition, DNA–DNA hybridization with reference strains of close phylogenetic relatives was between 11 and 19 %. On the basis of these data, the inclusion of strain SM19 T in the genus Marinobacter as a novel species is proposed, with the name Marinobacter lipolyticus sp. nov. The type strain of the novel species is SM19 T (=DSM 15157 T =NCIMB 13907 T =CIP 107627 T =CCM 7048 T ). Isolation and characterization of extracellular hydrolytic enzymes that show optimal activity at different salt concentrations constitutes an interesting research field with potential biotechnological applications. Availability of such enzymes would facilitate different industrial processes that require activity at high salt concentrations. Moderately halophilic bacteria have adapted to live in a wide range of salt concentrations (3–15 % NaCl) and constitute an interesting group of micro-organisms that could be used as a source of such salt-adapted enzymes (Ventosa et al., 1998). A screening programme to detect hydrolytic acti- vities, such as protease, amylase, cellulase, pullulanase and lipase, has recently been performed in different hypersaline environments of southern Spain (Sa ´nchez-Porro et al., 2003). This study revealed a wide diversity of moderately halophilic bacteria with the potential to hydrolyse a range of structurally non-related polymers. Among the isolates, 207 moderately halophilic bacteria that display lipolytic activity have been detected. Applications of lipolytic enzymes, which comprise mainly esterases and lipases, are widely found in the food, detergents, pharmaceutical and chemical industries (Jaeger et al., 1999; Pandey et al., 1999). A large number of microbial lipolytic enzymes has been identified and characterized to date; however, no lipolytic enzymes have so far been characterized from moderate halophiles. Taxonomic/phylogenetic studies performed on these halophilic, lipolytic enzyme producers accommodate them within different genera, such as Salinivibrio, Halo- monas, Chromohalobacter, Salibacillus, Marinococcus and Marinobacter. In this study, the most promising isolate among the lipolytic producers, strain SM19 T , was assigned to the genus Marinobacter. This genus was proposed by Gauthier et al. (1992), belongs to the c-subclass of the class Proteobacteria and, at the time of writing, includes two species with validly published names: Marinobacter hydro- carbonoclasticus (Gauthier et al., 1992) and Marinobacter aquaeolei (Nguyen et al., 1999). Species of this genus are able to degrade hydrocarbons and some crude oil components. In this work, we present a taxonomic/phylogenetic study of strain SM19 T , a moderately halophilic bacterium that shows lipolytic activity with potential industrial applications, in order to establish its exact taxonomic position. We show that it constitutes a novel species of the genus Marinobacter, for which we propose the name Marinobacter lipolyticus sp. nov. Strain SM19 T was isolated from saline soil in Ca ´diz, Spain. The following reference strains were used for comparative purposes: M. hydrocarbonoclasticus DSM 8798 T , M. hydro- carbonoclasticus DSM 50418 and Marinobacter aquaeolei DSM 11845 T . M. hydrocarbonoclasticus DSM 50418 was the type strain of the former species Pseudomonas nautica (Baumann et al., 1972), which was transferred to the genus Marinobacter following a polyphasic taxonomic approach (Spro ¨er et al., 1998) and, consequently, it has been included The GenBank/EMBL/DDBJ accession number for the 16S rDNA sequence of Marinobacter lipolyticus SM19 T is AY147906. 02528 G 2003 IUMS Printed in Great Britain 1383 International Journal of Systematic and Evolutionary Microbiology (2003), 53, 1383–1387 DOI 10.1099/ijs.0.02528-0