Cloning, Expression, Characterization and Immobilization of a Recombinant Carboxylesterase from the Halophilic Archaeon, Halobacterium salinarum NCR-1.

Only a few halophilic archaea producing carboxylesterases have been reported. The limited research on biocatalytic characteristics of archaeal esterases is primarily due to their very low production in native organisms. A gene encoding carboxylesterase from Halobacterium salinarum NRC-1 was cloned and successfully expressed in Haloferax volcanii. The recombinant carboxylesterase (rHsEst) was purified by affinity chromatography with a yield of 81%, and its molecular weight was estimated by SDS-PAGE (33 kDa). The best kinetic parameters of rHsEst were achieved using p-nitrophenyl valerate as substrate (KM = 78 µM, kcat = 0.67 s-1). rHsEst exhibited great stability to most metal ions tested and some solvents (diethyl ether, n-hexane, n-heptane). Purified rHsEst was effectively immobilized using Celite 545. Esterase activities of rHsEst were confirmed by substrate specificity studies. The presence of a serine residue in rHsEst active site was revealed through inhibition with PMSF. The pH for optimal activity of free rHsEst was 8, while for immobilized rHsEst, maximal activity was at a pH range between 8 to 10. Immobilization of rHsEst increased its thermostability, halophilicity and protection against inhibitors such as EDTA, BME and PMSF. Remarkably, immobilized rHsEst was stable and active in NaCl concentrations as high as 5M. These biochemical characteristics of immobilized rHsEst reveal its potential as a biocatalyst for industrial applications.

Diversity and Biotechnological Potential of Cultivable Halophilic and Halotolerant Bacteria from the "Los Negritos" Geothermal Area.

Soil salinization is negatively affecting soils globally, and the spread of this problem is of great concern due to the loss of functions and benefits offered by the soil resource. In the present study, we explored the diversity of halophilic and halotolerant microorganisms in the arable fraction of a sodic-saline soil without agricultural practices and two soils with agricultural practices (one sodic and one saline) near the geothermal area "Los Negritos" in Villamar, Michoacán state. This was achieved through their isolation and molecular identification, as well as the characterization of their potential for the production of metabolites and enzymes of biotechnological interest under saline conditions. Using culture-dependent techniques, 62 halotolerant and moderately halophilic strains belonging to the genera Bacillus, Brachybacterium, Gracilibacillus, Halobacillus, Halomonas, Kocuria, Marinococcus, Nesterenkonia, Oceanobacillus, Planococcus, Priestia, Salibactetium, Salimicrobium, Salinicoccus, Staphylococcus, Terribacillus, and Virgibacillus were isolated. The different strains synthesized hydrolytic enzymes under 15% (w/v) of salts, as well as metabolites with plant-growth-promoting (PGP) characteristics, such as indole acetic acid (IAA), under saline conditions. Furthermore, the production of biopolymers was detected among the strains; members of Bacillus, Halomonas, Staphylococcus, and Salinicoccus showed extracellular polymeric substance (EPS) production, and the strain Halomonas sp. LNSP3E3-1.2 produced polyhydroxybutyrate (PHB) under 10% (w/v) of total salts.

Genome analysis of haloalkaline isolates from the soda saline crater lake of Isabel Island; comparative genomics and potential metabolic analysis within the genus Halomonas.

BACKGROUND: Isabel Island is a Mexican volcanic island primarily composed of basaltic stones. It features a maar known as Laguna Fragatas, which is classified as a meromictic thalassohaline lake. The constant deposition of guano in this maar results in increased levels of phosphorus, nitrogen, and carbon. The aim of this study was to utilize high-quality genomes from the genus Halomonas found in specialized databases as a reference for genome mining of moderately halophilic bacteria isolated from Laguna Fragatas. This research involved genomic comparisons employing phylogenetic, pangenomic, and metabolic-inference approaches. RESULTS: The Halomonas genus exhibited a large open pangenome, but several genes associated with salt metabolism and homeostatic regulation (ectABC and betABC), nitrogen intake through nitrate and nitrite transporters (nasA, and narGI), and phosphorus uptake (pstABCS) were shared among the Halomonas isolates. CONCLUSIONS: The isolated bacteria demonstrate consistent adaptation to high salt concentrations, and their nitrogen and phosphorus uptake mechanisms are highly optimized. This optimization is expected in an extremophile environment characterized by minimal disturbances or abrupt seasonal variations. The primary significance of this study lies in the dearth of genomic information available for this saline and low-disturbance environment. This makes it important for ecosystem conservation and enabling an exploration of its biotechnological potential. Additionally, the study presents the first two draft genomes of H. janggokensis.

Extremely chaotolerant and kosmotolerant Aspergillus atacamensis - a metabolically versatile fungus suitable for recalcitrant biosolid treatment.

Obligate halophily is extremely rare in fungi. Nevertheless, Aspergillus atacamensis (strain EXF-6660), isolated from a salt water-exposed cave in the Coastal Range hills of the hyperarid Atacama Desert in Chile, is an obligate halophile, with a broad optimum range from 1.5 to 3.4 M of NaCl. When we tested its ability to grow at varied concentrations of both kosmotropic (NaCl, KCl, and sorbitol) and chaotropic (MgCl2, LiCl, CaCl2, and glycerol) solutes, stereoscopy and laser scanning microscopy revealed the formation of phialides and conidia. A. atacamensis EXF-6660 grew up to saturating levels of NaCl and at 2.0 M concentration of the chaotropic salt MgCl2. Our findings confirmed that A. atacamensis is an obligate halophile that can grow at substantially higher MgCl2 concentrations than 1.26 M, previously considered as the maximum limit supporting prokaryotic life. To assess the fungus' metabolic versatility, we used the phenotype microarray technology Biolog FF MicroPlates. In the presence of 2.0 M NaCl concentration, strain EXF-6660 metabolism was highly versatile. A vast repertoire of organic molecules (~95% of the substrates present in Biolog FF MicroPlates) was metabolized when supplied as sole carbon sources, including numerous polycyclic aromatic hydrocarbons, benzene derivatives, dyes, and several carbohydrates. Finally, the biotechnological potential of A. atacamensis for xenobiotic degradation and biosolid treatment was investigated. Interestingly, it could remove biphenyls, diphenyl ethers, different pharmaceuticals, phenols, and polyaromatic hydrocarbons. Our combined findings show that A. atacamensis EXF-6660 is a highly chaotolerant, kosmotolerant, and xerotolerant fungus, potentially useful for xenobiotic and biosolid treatments.

Identification by molecular techniques of halophilic bacteria producing important enzymes from pristine area in Campeche, Mexico / Identificação por técnicas moleculares de bactérias halofílicas que produzem enzimas importantes em área intocada de Campeche, México

Isla Arena is located in the coordinate 20° 70´ N - 90° 45´ W, from Campeche, Mexico. In these estuaries, the ocean mixes with fresh water, and ecosystems are concentrated where petenes and pink flamingos proliferate. Crustaceans and mollusks abound in the sea. Despite its enormous marine wealth, there are no studies carried out on which halophilic microorganisms are present in these waters. In this work, the diversity and structure of the microbial community was investigated through a metagenomics approach and corroborated for sequencing of 16S rRNA genes. It was found that the phylum Fimicutes predominates with more than 50%, in almost the same proportion of the class Bacilli and with almost 41% of relative abundance of the order Bacillales. The sequencing results showed that one of the samples presented a high percentage of similarity (99.75%) using the Nucleotide BLAST program with a peculiar microorganism: Bacillus subtilis. This microorganism is one of the best characterized bacteria among the gram-positive ones. Our results demonstrate that B. subtilis can be an efficient source of proteases, lipases and cellulases, from halophilic microbial communities located in poorly explored areas.

Isla Arena está localizada na coordenada 20°70’N - 90°45’W, de Campeche, México. Nesses estuários, o oceano se mistura com a água doce e os ecossistemas se concentram onde proliferam petenos e flamingos rosa. Crustáceos e moluscos abundam no mar. Apesar de sua enorme riqueza marinha, não há estudos realizados sobre a presença de microrganismos halofílicos nessas águas. Neste trabalho, a diversidade e estrutura da comunidade microbiana foram investigadas através de uma abordagem metagenômica e corroboradas para o sequenciamento de genes 16S rRNA. Verificou-se que o filo Fimicutes predomina com mais de 50%, quase na mesma proporção da classe Bacilli e com quase 41% de abundância relativa da ordem Bacillales. Os resultados do sequenciamento mostraram que uma das amostras apresentou alto percentual de similaridade (99,75%) pelo programa Nucleotide BLAST com um microrganismo peculiar: Bacillus subtilis. Nossos resultados demonstram que B. subtilis pode ser uma fonte eficiente de proteases, lipases e celulases, provenientes de comunidades microbianas halofílicas localizadas em áreas pouco exploradas.

Identification by molecular techniques of halophilic bacteria producing important enzymes from pristine area in Campeche, Mexico

Abstract Isla Arena is located in the coordinate 20° 70´ N - 90° 45´ W, from Campeche, Mexico. In these estuaries, the ocean mixes with fresh water, and ecosystems are concentrated where petenes and pink flamingos proliferate. Crustaceans and mollusks abound in the sea. Despite its enormous marine wealth, there are no studies carried out on which halophilic microorganisms are present in these waters. In this work, the diversity and structure of the microbial community was investigated through a metagenomics approach and corroborated for sequencing of 16S rRNA genes. It was found that the phylum Fimicutes predominates with more than 50%, in almost the same proportion of the class Bacilli and with almost 41% of relative abundance of the order Bacillales. The sequencing results showed that one of the samples presented a high percentage of similarity (99.75%) using the Nucleotide BLAST program with a peculiar microorganism: Bacillus subtilis. This microorganism is one of the best characterized bacteria among the gram-positive ones. Our results demonstrate that B. subtilis can be an efficient source of proteases, lipases and cellulases, from halophilic microbial communities located in poorly explored areas.

Resumo Isla Arena está localizada na coordenada 20°70N - 90°45W, de Campeche, México. Nesses estuários, o oceano se mistura com a água doce e os ecossistemas se concentram onde proliferam petenos e flamingos rosa. Crustáceos e moluscos abundam no mar. Apesar de sua enorme riqueza marinha, não há estudos realizados sobre a presença de microrganismos halofílicos nessas águas. Neste trabalho, a diversidade e estrutura da comunidade microbiana foram investigadas através de uma abordagem metagenômica e corroboradas para o sequenciamento de genes 16S rRNA. Verificou-se que o filo Fimicutes predomina com mais de 50%, quase na mesma proporção da classe Bacilli e com quase 41% de abundância relativa da ordem Bacillales. Os resultados do sequenciamento mostraram que uma das amostras apresentou alto percentual de similaridade (99,75%) pelo programa Nucleotide BLAST com um microrganismo peculiar: Bacillus subtilis. Nossos resultados demonstram que B. subtilis pode ser uma fonte eficiente de proteases, lipases e celulases, provenientes de comunidades microbianas halofílicas localizadas em áreas pouco exploradas.

Identification by molecular techniques of halophilic bacteria producing important enzymes from pristine area in Campeche, Mexico / Identificação por técnicas moleculares de bactérias halofílicas que produzem enzimas importantes em área intocada de Campeche, México

Abstract Isla Arena is located in the coordinate 20° 70´ N - 90° 45´ W, from Campeche, Mexico. In these estuaries, the ocean mixes with fresh water, and ecosystems are concentrated where petenes and pink flamingos proliferate. Crustaceans and mollusks abound in the sea. Despite its enormous marine wealth, there are no studies carried out on which halophilic microorganisms are present in these waters. In this work, the diversity and structure of the microbial community was investigated through a metagenomics approach and corroborated for sequencing of 16S rRNA genes. It was found that the phylum Fimicutes predominates with more than 50%, in almost the same proportion of the class Bacilli and with almost 41% of relative abundance of the order Bacillales. The sequencing results showed that one of the samples presented a high percentage of similarity (99.75%) using the Nucleotide BLAST program with a peculiar microorganism: Bacillus subtilis. This microorganism is one of the best characterized bacteria among the gram-positive ones. Our results demonstrate that B. subtilis can be an efficient source of proteases, lipases and cellulases, from halophilic microbial communities located in poorly explored areas.

Resumo Isla Arena está localizada na coordenada 20°70'N - 90°45'W, de Campeche, México. Nesses estuários, o oceano se mistura com a água doce e os ecossistemas se concentram onde proliferam petenos e flamingos rosa. Crustáceos e moluscos abundam no mar. Apesar de sua enorme riqueza marinha, não há estudos realizados sobre a presença de microrganismos halofílicos nessas águas. Neste trabalho, a diversidade e estrutura da comunidade microbiana foram investigadas através de uma abordagem metagenômica e corroboradas para o sequenciamento de genes 16S rRNA. Verificou-se que o filo Fimicutes predomina com mais de 50%, quase na mesma proporção da classe Bacilli e com quase 41% de abundância relativa da ordem Bacillales. Os resultados do sequenciamento mostraram que uma das amostras apresentou alto percentual de similaridade (99,75%) pelo programa Nucleotide BLAST com um microrganismo peculiar: Bacillus subtilis. Nossos resultados demonstram que B. subtilis pode ser uma fonte eficiente de proteases, lipases e celulases, provenientes de comunidades microbianas halofílicas localizadas em áreas pouco exploradas.

Identification by molecular techniques of halophilic bacteria producing important enzymes from pristine area in Campeche, Mexico / Identificação por técnicas moleculares de bactérias halofílicas que produzem enzimas importantes em área intocada de Campeche, México

Isla Arena is located in the coordinate 20° 70´ N - 90° 45´ W, from Campeche, Mexico. In these estuaries, the ocean mixes with fresh water, and ecosystems are concentrated where petenes and pink flamingos proliferate. Crustaceans and mollusks abound in the sea. Despite its enormous marine wealth, there are no studies carried out on which halophilic microorganisms are present in these waters. In this work, the diversity and structure of the microbial community was investigated through a metagenomics approach and corroborated for sequencing of 16S rRNA genes. It was found that the phylum Fimicutes predominates with more than 50%, in almost the same proportion of the class Bacilli and with almost 41% of relative abundance of the order Bacillales. The sequencing results showed that one of the samples presented a high percentage of similarity (99.75%) using the Nucleotide BLAST program with a peculiar microorganism: Bacillus subtilis. This microorganism is one of the best characterized bacteria among the gram-positive ones. Our results demonstrate that B. subtilis can be an efficient source of proteases, lipases and cellulases, from halophilic microbial communities located in poorly explored areas.(AU)

Isla Arena está localizada na coordenada 20°70N - 90°45W, de Campeche, México. Nesses estuários, o oceano se mistura com a água doce e os ecossistemas se concentram onde proliferam petenos e flamingos rosa. Crustáceos e moluscos abundam no mar. Apesar de sua enorme riqueza marinha, não há estudos realizados sobre a presença de microrganismos halofílicos nessas águas. Neste trabalho, a diversidade e estrutura da comunidade microbiana foram investigadas através de uma abordagem metagenômica e corroboradas para o sequenciamento de genes 16S rRNA. Verificou-se que o filo Fimicutes predomina com mais de 50%, quase na mesma proporção da classe Bacilli e com quase 41% de abundância relativa da ordem Bacillales. Os resultados do sequenciamento mostraram que uma das amostras apresentou alto percentual de similaridade (99,75%) pelo programa Nucleotide BLAST com um microrganismo peculiar: Bacillus subtilis. Nossos resultados demonstram que B. subtilis pode ser uma fonte eficiente de proteases, lipases e celulases, provenientes de comunidades microbianas halofílicas localizadas em áreas pouco exploradas.(AU)

Proteolytic Activity Assays in Haloarchaea.

Extreme halophilic archaea (haloarchaea) have adapted their physiology and biomolecules to thrive in saline environments (>2 M NaCl). Many haloarchaea produce extracellular hydrolases (including proteases) with potential biotechnological applications, which require unusual high salt concentrations to attain their function and maintain their stability. These conditions restrict many of the standard methods used to study these enzymes such as activity determination and/or protein purification. Here, we describe basic protocols to detect and measure extracellular proteolytic activity in haloarchaea including casein hydrolysis on agar plates, quantitative proteolytic activity determination by the azocasein assay and gelatin zymography in presence of the compatible solute glycine-betaine.

Cell Adhesion and Biofilm Formation Analysis.

Cell adhesion to surfaces and ulterior biofilm formation are critical processes in microbial development since living in biofilms is the preferred way of life within microorganisms. These processes are known to influence not only microorganisms development in the environment, but also their participation in biotechnological processes and have been the focus of intense research that as a matter of fact, was mainly directed to the bacterial domain. Archaea also adhere to surfaces and have been shown forming biofilms, but studies performed until present did not exploit the diversity of methods probed to be useful along bacterial biofilm research.An experimental setup is described here with the aim of stimulating archaeal biofilm research. It can be used for studying cell adhesion and biofilm formation under controlled flow conditions and allows performing in situ optical microscopy (phase contrast, fluorescence, or confocal) and/or spectroscopic techniques (UV-Vis, IR, or Raman) to determine structural and functional biofilm features and their evolution in time. Variants are described with specific aims as working in anaerobiosis and allow sampling of biological material along time.

Surviving in the Brine: A Multi-Omics Approach for Understanding the Physiology of the Halophile Fungus Aspergillus sydowii at Saturated NaCl Concentration.

Although various studies have investigated osmoadaptations of halophilic fungi to saline conditions, only few analyzed the fungal mechanisms occurring at saturated NaCl concentrations. Halophilic Aspergillus sydowii is a model organism for the study of molecular adaptations of filamentous fungi to hyperosmolarity. For the first time a multi-omics approach (i.e., transcriptomics and metabolomics) was used to compare A. sydowii at saturated concentration (5.13 M NaCl) to optimal salinity (1 M NaCl). Analysis revealed 1,842 genes differentially expressed of which 704 were overexpressed. Most differentially expressed genes were involved in metabolism and signal transduction. A gene ontology multi-scale network showed that ATP binding constituted the main network node with direct interactions to phosphorelay signal transduction, polysaccharide metabolism, and transferase activity. Free amino acids significantly decreased and amino acid metabolism was reprogrammed at 5.13 M NaCl. mRNA transcriptional analysis revealed upregulation of genes involved in methionine and cysteine biosynthesis at extreme water deprivation by NaCl. No modifications of membrane fatty acid composition occurred. Upregulated genes were involved in high-osmolarity glycerol signal transduction pathways, biosynthesis of ß-1,3-glucans, and cross-membrane ion transporters. Downregulated genes were related to the synthesis of chitin, mannose, cell wall proteins, starvation, pheromone synthesis, and cell cycle. Non-coding RNAs represented the 20% of the total transcripts with 7% classified as long non-coding RNAs (lncRNAs). The 42% and 69% of the total lncRNAs and RNAs encoding transcription factors, respectively, were differentially expressed. A network analysis showed that differentially expressed lncRNAs and RNAs coding transcriptional factors were mainly related to the regulation of metabolic processes, protein phosphorylation, protein kinase activity, and plasma membrane composition. Metabolomic analyses revealed more complex and unknown metabolites at saturated NaCl concentration than at optimal salinity. This study is the first attempt to unravel the molecular ecology of an ascomycetous fungus at extreme water deprivation by NaCl (5.13 M). This work also represents a pioneer study to investigate the importance of lncRNAs and transcriptional factors in the transcriptomic response to high NaCl stress in halophilic fungi.

Seawater-based biorefineries: A strategy to reduce the water footprint in the conversion of lignocellulosic biomass.

Biorefineries are an essential step towards implementing a circular economy in the long term. They are based on renewable raw materials and must be designed holistically, recovering building blocks from being converted into several products. Lignocellulosic biomass is considered a critical pillar for a biologically based economy and a high value-added feedstock. The separation of the structural complexity that makes up the biomass allows the development of different product flows. Chemical, physical, and biological processes are evaluated for fractionation, hydrolysis, and fermentation processes in biorefineries; however, the volume of freshwater used affects water safety and increases the economic costs. Non-potable-resources-based technologies for biomass bioconversion are essential for biorefineries to become environmentally and economically sustainable systems. Studies are being carried out to substitute freshwater with seawater to reduce the water footprint. Accordingly, this review addresses a comprehensive discussion about seawater-based biorefineries focusing on lignocellulosic biomass conversion in biofuel and value-added products.

Hygienic and sanitary characteristics of dry salted fish marketed in Porto Velho city, Rondônia ­ Brazil / Características higiênico-sanitárias de pescado salgado seco comercializado em Porto Velho, Rondônia ­ Brasil

Handcrafted salted fish is marketed weekly in retail markets and public fairs in the Porto Velho city, Rondônia sate, Brazil. Knowing the microbiological quality of these products is essential for public health, given that such products are not subject to any quality control. The aimed of the study was to evaluate the hygienic-sanitary characteristics and the moisture content of pirarucu and salted and dried shrimp marketed in the Porto Velho city. Twenty samples were collected, 10 pirarucu and 10 shrimp, in February and June 2019. For microbiological analysis, surface plating was performed using acidified potato agar, for molds and yeasts, and PCA agar for halophilic bacterias. Moisture was determined by gravimetry, using an oven at 105° C. Results for molds and yeasts on pirarucu ranged <10 log CFU/g (absent) to 3 log CFU/g. For shrimp, values ranged <10 log CFU/g to 3.57 log CFU/g. For halophilic bacterias, contents ranged <10 log CFU/g to 6.30 log CFU/g in pirarucu samples and <10 log CFU/g to 6.97 log CFU/g in shrimp samples. The variation in moisture content ranged 36.99 to 54.31% for pirarucu, and 40.6 to 56.82% for shrimp. The results obtained may be related to poor hygienic conditions in processing, the lack of hygiene of utensils and places for handling, or even the quality of the raw material used.(AU)

Pescado salgado preparado artesanalmente é semanalmente comercializado em mercados varejistas e feiras públicas na cidade de Porto Velho, Rondônia. Conhecer a qualidade microbiológica desses produtos é essencial para a saúde pública, haja visto, que tais produtos não estão sujeitos a nenhum controle de qualidade. O objetivo do estudo foi avaliar as caracterís-ticas higiênico-sanitárias e o teor de umidade de pirarucus e camarões salgados e secos comercializados em Porto Velho. Foram coletadas 20 amostras, 10 de pirarucu e 10 de camarão, em fevereiro e junho de 2019. Para as análises microbiológicas foi realizado o plaqueamento em superfície usando-se ágar batata acidificado, para bolores e leveduras, e ágar PCA para as bacté-rias halofílicas. A umidade foi determinada por gravimetria, com uso de estufa a 105°C. Os resultados para bolores e leveduras em pirarucu variaram de <10 log UFC/g (ausente) a 3 log UFC/g. Para os camarões os valores variaram de <10 log UFC/g a 3,57 log UFC/g. Para as bactérias halofílicas os teores variaram de <10 log UFC/g a 6,30 log UFC/g nas amostras de pirarucu e de <10 log UFC/g a 6,97 log UFC/g nas amostras de camarão. A variação nos teores de umidade foi de 36,99 a 54,31% para o pirarucu, e de 40,6 a 56,82% para o camarão. Os resultados obtidos podem estar relacionados às más condições higiênicas no processamento, à falta de higiene dos utensílios e dos locais de manipulação, ou ainda, à qualidade da matéria-prima empregada.(AU)

Thalassobacillus, a genus of extreme to moderate environmental halophiles with biotechnological potential.

Thalassobacillus is a moderately halophilic genus that has been isolated from several sites worldwide, such as hypersaline lakes, saline soils, salt flats, and volcanic mud. Halophilic bacteria have provided functional stable biomolecules in harsh conditions for industrial purposes. Despite its potential biotechnological applications, Thalassobacillus has not been fully characterized yet. This review describes the Thalassobacillus genus, with the few species reported, pointing out its possible applications in enzymes (amylases, cellulases, xylanases, and others), biosurfactants, bioactive compounds, biofuels production, bioremediation, and plant growth promotion. The Thalassobacillus genus represents a little-explored biological resource but with a high potential.

Effect of Carbon Sources in Carotenoid Production from Haloarcula sp. M1, Halolamina sp. M3 and Halorubrum sp. M5, Halophilic Archaea Isolated from Sonora Saltern, Mexico.

The isolation and molecular and chemo-taxonomic identification of seventeen halophilic archaea from the Santa Bárbara saltern, Sonora, México, were performed. Eight strains were selected based on pigmentation. Molecular identification revealed that the strains belonged to the Haloarcula, Halolamina and Halorubrum genera. Neutral lipids (quinones) were identified in all strains. Glycolipid S-DGD was found only in Halolamina sp. strain M3; polar phospholipids 2,3-O-phytanyl-sn-glycerol-1-phosphoryl-3-sn-glycerol (PG), 2,3-di-O-phytanyl-sn-glycero-1-phospho-3'-sn-glycerol-1'-methyl phosphate (PGP-Me) and sodium salt 1-(3-sn-phosphatidyl)-rac-glycerol were found in all the strains; and one unidentified glyco-phospholipid in strains M1, M3 and M4. Strains M1, M3 and M5 were selected for further studies based on carotenoid production. The effect of glucose and succinic and glutamic acid on carotenoid production was assessed. In particular, carotenoid production and growth significantly improved in the presence of glucose in strains Haloarcula sp. M1 and Halorubrum sp. M5 but not in Halolamina sp. M3. Glutamic and succinic acid had no effect on carotenoid production, and even was negative for Halorubrum sp. M5. Growth was increased by glutamic and succinic acid on Haloarcula sp. M1 but not in the other strains. This work describes for first time the presence of halophilic archaea in the Santa Bárbara saltern and highlights the differences in the effect of carbon sources on the growth and carotenoid production of haloarchaea.

Genome sequence of Vibrio fluvialis 362.3 isolated from coral Mussismilia braziliensis reveals genes related to marine environment adaptation.

Vibrio fluvialis is a halophilic bacterium frequently found in estuarine and coastal waters environments. The strain 362.3 was isolated from Mussismilia braziliensis coral of Abrolhos Bank. In this study, to gain insights into the marine adaptation in V. fluvialis, we sequenced the genome of 362.3 strain, which comprised 4,607,294 bp with a G + C content of 50.2%. In silico analysis showed that V. fluvialis 362.2 encodes genes related to chitin catabolic pathway, iron metabolism, osmotic stress and membrane transport.

A novel halophilic Exiguobacterium mexicanum strain removes nitrogen from saline wastewater via heterotrophic nitrification and aerobic denitrification.

The utilization of halophilic bioresources is limited due to a lack of isolation and characterization work. A halophilic bacterium strain SND-01 of Exiguobacterium mexicanum was isolated in this study, which is the first report on its novel function in heterotrophic nitrification-aerobic denitrification (HN-AD). The strain SND-01 is slightly halophilic, surviving at 0 up to 9% (w/v) salinity. When utilizing ammonium, nitrate or nitrite as the sole nitrogen source in aerobic conditions, the isolated strain showed the maximum nitrogen removal rate of 2.24 ± 0.14 mg/(L·h), 3.63 ± 0.21 mg/(L·h) and 2.30 ± 0.23 mg/(L·h), respectively. Functional genes and key enzymes involved in heterotrophic-aerobic nitrogen transformations were characterized, establishing the pathway of HN-AD. The nitrogen removal via HN-AD is dependent on the C/N ratio, salinity and temperature. The halophilic Exiguobacterium mexicanum strain SND-01 shows a significant potential in biotreatment of saline wastewater in an easy and cost-effective way.

Salifodinibacter halophilus gen. nov., sp. nov., a halophilic gammaproteobacterium in the family Salinisphaeraceae isolated from a salt mine in the Colombian Andes.

Two morphologically similar halophilic strains, named USBA 874 and USBA 960T, were isolated from water and sediment samples collected from the Zipaquirá salt mine in the Colombian Andes. Both isolates had non-spore-forming, Gram-stain-negative and motile cells that grew aerobically. The strains grew optimally at 30 °C, pH 7.0 and with 25 % NaCl (w/v). The isolates showed almost identical 16S rRNA gene sequences (99.0 % similarity). The predominant quinones of USBA-960T were Q-8, Q-7 and Q-9. The major cellular fatty acids were C19 : 0 cyclo ω8c, C18 : 0 and C16 : 0. According to 16S rRNA gene sequencing, the closest phylogenetic relatives are Salinisphaera species (similarity between 93.6 and 92.3 %), Abyssibacter profundi OUC007T (88.6 %) and Oceanococcus atlanticus 22II-S10r2T (88.7 %). In addition, the result of genome blast distance phylogeny analysis between strains USBA 874 and USBA 960T, Salinisphaera halophila (YIM 95161T), Salinisphaera shabanensis (E1L3AT), Salinisphaera orenii (MK-B5T) and Salinisphaera japonica (YTM-1T) was 18.5 %. Other in silico species delineation analyses also showed low identity such as ANIb and ANIm values (<69.0 and <84.0 % respectively), TETRA (<0.81) and AAI values (<0.67). Genome sequencing of USBA 960T revealed a genome size of 2.47 Mbp and a G+C content of 59.71 mol%. Phylogenetic analysis of strains USBA 874 and USBA 960T indicated that they formed a different lineage within the family Salinisphaeraceae. Based on phenotypic and chemotaxonomic characteristics, phylogenetic analysis and DNA-DNA relatedness values, along with identity at whole genome level, it can be concluded that strains USBA 960T and USBA 874 represent a novel genus of the family Salinisphaeraceae and the name Salifodinibacter halophilus gen. nov., sp. nov. is proposed. The type strain is USBA 960T (CMPUJ U095T=CECT 30006T).

New insights into halophilic prokaryotes isolated from salting-ripening anchovies (Engraulis anchoita) process focused on histamine-degrading strains.

Salted and ripened fish foods are susceptible to cause histamine poisoning. The present study focuses on microbial histamine degradation from high salted fermented fishery products to deepen our understanding about this new and growing field of research. As a result of this first study related to salted-ripened anchovies (Engraulis anchoita), fifty seven moderate and extreme halophilic microbial isolates from salt and salted-ripened anchovy processes were characterized in terms of their phenotype and histamine-degrading capacity. Only 7%-4 isolates-were able to degrade histamine. None of the histamine-degrading isolates presented proteolytic and/or lipolytic activity. One of them designated A18 was chemotactic toward histamine, an interesting property not previously reported for that chemoattractant. However, the S18 and A18 isolates, genotypically identified as Halobacterium sp. and Halomonas sp. respectively, produced indole and/or H2S, both undesirable characteristics associated to off-flavors occurrence. On the other hand, A28 and S20, identified as Halovibrio sp. and Halobacterium sp. respectively, presented desirable properties, such as cytochrome oxidase and catalase activity, and non-production of H2S and indole. These strains also showed characteristics previously reported as dominant in the ripened stage. The results are promising, and A28 and S20 may have the desirable features to improve the anchovy salting-ripening process.

Biofilms of Halobacterium salinarum as a tool for phenanthrene bioremediation.

The use of hyperhalophilic microorganisms is emerging as a sustainable alternative to clean hydrocarbon-polluted hypersaline water bodies. In line with this practice, this work reports on the ability of the archaeon Halobacterium salinarum to develop biofilms on a solid surface conditioned by the presence of phenanthrene crystals, which results in the removal of the contaminating compound. The cell surface hydrophobicity does not change during the removal process and this organism is shown to constitutively produce a surfactant molecule with specific action on aromatic hydrocarbons, both indicating that phenanthrene removal might proceed through a non-contact mechanism. A new approach is presented to follow the process in situ through epifluorescence microscopy by monitoring phenanthrene auto-fluorescence.