Complete Genome Sequence of Marinobacter flavimaris LMG 23834T, Which Is Potentially Useful in Bioremediation

Deep Hypersaline Anoxic Basins as Untapped Reservoir of Polyextremophilic Prokaryotes of Biotechnological Interest

Deep-sea hypersaline anoxic basins (DHABs) are considered to be among the most extreme ecosystems on our planet, allowing only the life of polyextremophilic organisms. DHABs’ prokaryotes exhibit extraordinary metabolic capabilities, representing a hot topic for microbiologists and biotechnologists. These are a source of enzymes and new secondary metabolites with valuable applications in different biotechnological fields. Here, we review the current knowledge on prokaryotic diversity in DHABs, highlighting the biotechnological applications of identified taxa and isolated species. The discovery of new species and molecules from these ecosystems is expanding our understanding of life limits and is expected to have a strong impact on biotechnological applications.

Draft Genome Sequence of Marinobacter sp. Strain LZ-6, Isolated from the Toxic Dinoflagellate Alexandrium catenella

Here, we report the draft genome sequence of Marinobacter sp. strain LZ-6, isolated from the cell culture of a toxic marine dinoflagellate, Alexandrium catenella LZT09. A total of 4,405 predicted protein-coding genes were revealed, including those associated with initial biosynthesis of the key intermediate of paralytic shellfish poisoning toxins (PSTs), namely saxitoxin, and with toxic compound extrusion.

Marinobacter maroccanus sp. nov., a moderately halophilic bacterium isolated from a saline soil

During the taxonomic investigation of exopolymer-producing halophilic bacteria, a rod-shaped, motile, Gram-stain-negative, halophilic bacterium, designated strain N4^T, was isolated from a saline soil located in northern Morocco. Optimal growth of the isolate was at 30-37 ºC and at pH 7.0-8.0, in the presence of 5-7 % (w/v) NaCl. Useful characteristics for the phenotypic differentiation of strain N4^T from other Marinobacter species included α-chymotrypsin and α-glucosidase activities and the carbohydrate assimilation profile. The major fatty acids detected in strain N4^T were C16:0 and C18:1ω9c and the predominant respiratory quinone was ubiquinone-9. Sequence analysis of the 16S rRNA gene indicated that strain N4^T belonged to the genus Marinobacter and was closely related to the type strains of Marinobacter adhaerens (99.04 % similarity), Marinobacter salsuginis (98.97 %) and Marinobacter flavimaris (98.36 %). Phylogenetic analysis of the rpoD gene sequence also showed that the nearest neighbours of strain N4^T were M. salsuginis (91.49 % similarity), M. adhaerens and M. flavimaris (90.63 %). Strain N4^T showed 87.98 % average nucleotide identity with M. flavimaris and M. salsuginis, and 87.47 % with M. adhaerens. Regarding in-silico genome-to-genome distance, strain N4^T showed DNA-DNA hybridization values of 33.30 % with M. adhaerens, 34.60 % with M. flavimaris and 34.70 % with M. salsuginis. The DNA G+C content of strain N4^T was 57.3 mol%. Based on the results of phenotypic characterization, phylogenetic analysis and genome comparison, strain N4^T represents a novel species of the genus Marinobacter, for which the name Marinobacter maroccanus sp. nov. is proposed. The type strain is N4^T (=CECT 9525^T=LMG 30466^T).