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The composition and distribution of alkylbenzenes, alkyltoluenes, and 2-methyl-2-(4,8,12-trimethyltridecyl)chromans (MTTC) in the aromatic hydrocarbon fraction isolated from the Lower Permian silty-clayey and salt rocks of the Upper Pechora potassium–magnesium salt basin (Yakshinskoe deposit) are presented. The studies have shown the wide distribution of alkylbenzenes and alkyltoluenes under hypersaline environment (stages of the halite and sylvite precipitation) at low organic matter maturity. The revealed differences in n-alkylbenzenes and n-alkyltoluene distributions are associated with the predominance of various biological precursors (halophilic archaea, prasinophytes, planktonic algae, etc.) during the salt deposition of the Upper Pechora Basin. Our data confirmed the predominance of hexadecylbenzene (C22) among n-alkylbenzenzenes under hypersaline environments. The presence of phytanylbenzene and phytanyltoluene was established in the rocks of the Upper Pechora salt basin. It was found that the maximum content of phytanylbenzene is correlated with elevated contents of phytane and hexadecylbenzene, which suggests their common source and allows us to consider these compounds as indicators of paleohypersalinity. The abundance of 5,7,8-trimethyl-MTTC at low concentrations of mono- and dimethyl-MTTC indicates significant input of fresh water into the evaporite basin during the deposition of the underlying rock salt horizon.

Halophilic archaea are one of the microorganism groups that have adapted to living in high saline environments and are important in terms of their potential use in biotechnology industry. One of the most important compounds they have, carotenoid, is used in food, cosmetics, and medical industries. The selected strain was identified as an extremely halophilic and thermophilic archaeon, Haloterrigena thermotolerans K15, based on morphological, biochemical, and physiological evidence as well as 16S rRNA analysis and screened by a scanning electron microscope and an atomic force microscope for the first time. The carotenoid contents of H. thermotolerans K15 isolated from Salt Lake (Tuz Golu, Turkey) were determined by RP-HPLC–DAD and their isomers were characterized according to UV–Vis spectra by cis peak intensity and spectral fine structure. In addition to all-trans bacterioruberin as a major carotenoid, many isomers of the bacterioruberin such as monoanhydrobacterioruberin and bisanhydrobacterioruberin were also found. The antioxidant activity of carotenoid extract from H. thermotolerans was analyzed by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging method. The carotenoid extract showed antioxidant activity statistically significantly higher than ascorbic acid and butylated hydroxytoluene as reference compounds (p

A moderately halophilic bacterium isolated from the water samples collected from a salt field, Salinivibrio sp. TGB10 was found capable of producing poly-3-hydroxybutytate (PHB) from various sugars. Cell dry weight (CDW) of 8.82 g/L and PHB titer of 6.84 g/L were obtained using glucose as the carbon source after 24 h of cultivation in shake flasks. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was synthesized when propionate was provided as secondary carbon source. Salinivibrio sp. TGB10 exhibited favorable tolerance to propionate. The use of 8 g/L propionate and 20 g/L glucose as combinational substrates yielded 1.45 g/L PHBV with a 3-hydroxyvalerate monomer content of 72.02 mol% in flask cultures. In bioreactor study, CDW of 33.45 g/L and PHBV titer of 27.36 g/L were obtained after 108 h of fed-batch cultivation. The results indicated that Salinivibrio sp. TGB10 is a promising halophilic bacterium for the production of PHBV with various polymer compositions.

Higher plants and microorganisms produce uricase that oxidizes uric acid to allantoin. The lack of uricase in higher primates and humans causes uric acid accumulation. Today, the uricase treatment of hyperuricemia has been considered as a remedy. Uricases vary slightly in their origins and structures. Halophilic bacteria synthesize uricase with acidic amino acids at the surface. Fifty-eight halophilic strains isolated from Iranian saline lakes were screened for uricase production. The bacteria were cultured on a medium containing 5% salt and 0.3% uric acid and were assayed at 293 nm. The cultures were optimized by analyzing the effect of physical and chemical factors on the bacterial biomass and uricase production. Out of 18 strains, those were positive for uric-lytic activity, Halobacillus sp. strain GCFx14 with the highest uricase activity at (0.131 U/ml) showed the closest relationship to Halobacillus trueperi (99.00%), and Halobacillus profundi and Halobacillus faecis (98.87%), respectively. The optimum temperature for uricase activity (0.261 U/ml) was 40 °C. The mass of Halobacillus sp. strain GCFx14 produced uricase with the activity of 0.233 U/ml at pH 9, while 1% salinity led to 0.215 U/ml activity of uricase. pH of 8.0, temperature of 35 $$^\circ $$ C, salinity of 2.5%, and 0.2% uric acid were the optimum conditions to produce the highest amount of uricase in Halobacillus sp. strain GCFx14. The highest induction of uricase production in the strain was obtained using yeast extract and peptone (meat) as nitrogen and carbon sources.

Proteins of halophilic organisms, which accumulate molar concentrations of KCl in their cytoplasm, have a much higher content in acidic amino acids than proteins of mesophilic organisms. It has been proposed that this excess is necessary to maintain proteins hydrated in an environment with low water activity, either via direct interactions between water and the carboxylate groups of acidic amino acids or via cooperative interactions between acidic amino acids and hydrated cations. Our simulation study of five halophilic proteins and five mesophilic counterparts does not support either possibility. The simulations use the AMBER ff14SB force field with newly optimized Lennard-Jones parameters for the interactions between carboxylate groups and potassium ions. We find that proteins with a larger fraction of acidic amino acids indeed have higher hydration levels, as measured by the concentration of water in their hydration shell and the number of water/protein hydrogen bonds. However, the hydration level of each protein is identical at low (bKCl = 0.15 mol/kg) and high (bKCl = 2 mol/kg) KCl concentrations; excess acidic amino acids are clearly not necessary to maintain proteins hydrated at high salt concentration. It has also been proposed that cooperative interactions between acidic amino acids in halophilic proteins and hydrated cations stabilize the folded protein structure and would lead to slower dynamics of the solvation shell. We find that the translational dynamics of the solvation shell is barely distinguishable between halophilic and mesophilic proteins; if such a cooperative effect exists, it does not have that entropic signature.

Total synthesis of the pentasaccharide repeating unit of the OPS from Halomonas ventosae RU5S2EL is accomplished through a [3+2] block strategy. Picoloyl-induced hydrogen-bond-assisted aglycon delivery (HAD) is used for two consecutive 1,2-cis-l-rhamnosylations, and remote participation is used for α-selective glucosylation. The choice of 2-aminoethyl glycoside at the reducing end is opted for, leaving the scope for further glycoconjugate formation without hampering the reducing-end stereochemistry.

The available information on de novo synthesized compatible solutes in response to high medium salinity by bacteria of the Chromohalobacter genus is limited to studies of the mesophilic moderately halophilic strain Chromohalobacter salexigens DSM 3043T. Therefore, there is a need for studies of representatives of other species of the Chromohalobacter genus of the Halomonadaceae family. A moderately halophilic psychrotolerant bacterium, strain N1, closely related to the species Chromohalobacter japonicus was isolated from the salt crust of a rock salt waste pile in Berezniki, Perm Krai, Russia. An intracellular pool of compatible solutes of strain N1 was investigated by NMR spectroscopy. Cells grown in the presence of 5% NaCl at optimal growth temperature (28 °C) accumulated ectoine, glutamate, N(4)-acetyl-l-2,4-diaminobutyrate (NADA), alanine, trehalose, hydroxyectoine, and valine. Such a combination of compatible solutes is unique and distinguishes the strain from C. salexigens DSM 3043T. Hyperosmotic stress induced by 15% NaCl caused the accumulation of ectoine, NADA, and hydroxyectoine but led to a decrease in the amount of alanine, valine, and trehalose. The intracellular pool of glutamate was not significantly changed. A reduction of the growth temperature from 28 to 5 °C led to an increase in the amount of ectoine, NADA, trehalose, and hydroxyectoine. Ectoine was the major compatible solute.

Sabkhas in Kuwait are unique hypersaline marine environments under-explored for bacterial community composition and bioprospecting. The 16S rRNA sequence analysis of 46 isolates with distinct morphology from two Kuwait sabkhas recovered 11 genera. Phylum Firmicutes dominated these isolates, and Bacillus (32.6%) was recovered as the dominant genera, followed by Halococcus (17.4%). These isolates were moderately halophilic, and some of them showed tolerance and growth at extreme levels of salt (20%), pH (5 and/or 11), and temperature (55 °C). A higher percentage of isolates harbored protease (63.0), followed by DNase (41.3), amylase (41.3), and lipase (32.6). Selected isolates showed antimicrobial activity against E. faecalis and isolated Halomonas shengliensis, and Idiomarina piscisalsi harbored gene coding for dNDP-glucose 4,6-dehydratase (Glu 1), indicating their potential to produce biomolecules with deoxysugar moieties. Palmitic acid or oleic acid was the dominant fatty acid, and seven isolates had some polyunsaturated fatty acids (linolenic or γ-linolenic acid). Interestingly, six isolates belonging to Planococcus and Oceanobacillus genus produced squalene, a bioactive isoprenoid molecule. Their content increased 30-50% in the presence of Terbinafine. The potential bioactivities and extreme growth conditions make this untapped bacterial diversity a promising candidate for future bioprospecting studies.

Endoglucanase, particularly those, which can withstand extreme conditions are in demand in different industrial settings. In this direction, a halophilic cellulolytic bacterial strain EN1 was isolated from decomposed wood particles of India’s largest inland hypersaline Sambhar Lake in Rajasthan. Based on 16S rRNA gene sequence homology, the bacterium was identified as Salisediminibacterium halotolerans. It constitutively secretes extracellular endoglucanase in heterotrophic culture supernatant supplemented with or without carboxy-methyl cellulose. EN1 endoglucanase is active at pH 8.0–11.0, and 10–30% NaCl with optimum values of pH 11.0, and 25% NaCl. Under these optimum conditions, the enzyme retained up to 90% activity for 8 h. Activity was enhanced by some metal ions (5 mM) in order of Cu2+ (273%), Ni2+ (139%) and Fe2+ (125%); and decreased by Mg2+ (72%) and EDTA (56%). The enzyme was stable in different organic solvents (30% v/v), namely ethanol (108%), hexane (95%), methanol (93%), and iso-propanol (92%). The endoglucanase was effectively used for in situ saccharification of alkali-pretreated rice straw with 50 µg mL−1 reducing ends released after 120 h. These unique features of the extracellular endoglucanase reported for the first time from the genera Salisediminibacterium indicate its prospects in different industrial settings particularly for bioethanol production.

Ectoine and hydroxyectoine are well known extremolytes that accumulate in halophilic and halotolerant microorganisms. They are investigated as protein stabilizers and as excipients in protein formulations and biopharmaceuticals. However, their effect is quite controversial. In this work, the influence of both extremolytes on mink growth hormone as a model protein was studied by fluorescence spectroscopy. The study revealed that the fluorescence quenching of protein tryptophan by ectoine and hydroxyectoine differs and is dependent on the pH value of solution. Moreover, the quenching mode by ectoine and hydroxyectoine was compared with a well-known quencher acrylamide. The differences in the extremolytes interaction with protein revealed by fluorescence spectroscopy could be related to their different effect as protein stabilizers under various conditions.

A mannan-degrading halophilic archaeal strain, MD130-1T, was isolated from a commercial salt sample. Cells were motile, rod-shaped, and stained Gram-negative. Colonies were pink pigmented. Strain MD130-1T was able to grow at 1.5–4.6 M NaCl (optimum, 3.6 M) at pH 6.0–8.0 (optimum, pH 7.0) and at 25–50 °C (optimum, 40 °C). The DNA G+C content was 62.1 mol% (genome). The orthologous 16S rRNA gene sequence showed the highest similarity (99.4 %) to those of Haloarcula japonica JCM 7785T and Haloarcula hispanica JCM 8911T. The values of genome relatedness between strain MD130-1T and Haloarcula species were 84.33–85.96 % in ANIb and 30.4–32.9 % using GGDC formula 2. The polar lipids of strain MD130-1T were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and triglycosyl diether-2. Based on the results of phenotypic and phylogenetic analyses, the strain represents a new species of the genus Haloarcula , for which the name Haloarcula mannanilytica sp. nov. is proposed. The type strain is MD130-1T (=JCM 33835T=KCTC 4287T) isolated from commercial salt made in Ishikawa prefecture, Japan.

Two halophilic archaeal strains, C90T and YPL13T, were isolated from a salt lake and a salt mine in PR China. The two strains were found to form two clusters (97.5 and 89.5 % similarity between them, respectively) separating them from the three current members of the genus Natronomonas (95.4–97.0 % and 86.6–89.3 % similarity, respectively) on the basis of the 16S rRNA and rpoB′ gene sequence similarities and phylogenetic analysis. Diverse phenotypic characteristics differentiate strains C90T and YPL13T from current Natronomonas members. The polar lipids of strain C90T were phosphatidic acid, phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulphate, two unidentified glycolipids, a major glycolipid and a minor glycolipid, while those of strain YPL13T were PG, PGP-Me, two unidentified phospholipids and a glycolipid. The average nucleotide identity (ANI) and in silico DNA–DNA hybridization (isDDH) values between the two strains were 79.8 and 27.1 %, respectively, which were much lower than the threshold values proposed as a species boundaries (ANI 95–96 % and isDDH 70 %), which revealed that the two strains represent two novel species; these values (ANI 76.6–80.0 % and isDDH 21.6–27.0 %) of the strains examined in this study and the current members of Natronomonas are much lower than the recommended threshold values, suggesting that strains C90T and YPL13T represent two genomically different species of Natronomonas . These results showed that strains C90T (=CGMCC 1.13738T=JCM 32961T) and YPL13T (=CGMCC 1.13884T=JCM 31111T) represent two novel species of Natronomonas , for which the names Natronomonas halophila sp. nov. and Natronomonas salina sp. nov. are proposed.

1-Carboxymethyl-5-halo-6-hydroxy-5-methyl-5,6-dihydrouracils and 1-carboxymethyl-6-hydroxy-5-methyl-5-mtro-5,6-dihydrouracils were synthesized for the first time by oxidative halogenation and nitration of 1-carboxymethyl-5-methyluracil. Dihydrouracil derivatives bearing a Br atom at position C(5) and a hydroxy group at position C(6) treated with Ac2O undergo deoxyhalogenation.

The halophilic consortium enriched from seagrass present in Jeddah coast region, Saudi Arabia, potently degraded different petroleum hydrocarbons such as phenanthrene (PHE), fluorene (FLU), pyrene (PY) and hexadecane (HD) under saline condition (4%). The halophilic consortium recorded complete degradation of PHE and FLU up to 400 ppm. At 600 ppm of PHE and FLU, the consortium revealed 98% and 99% degradation in 10 days. Further increase in concentration to 800 ppm showed slight decline in the percent degradation of PHE (92%) and FLU (95%) by the halophilic consortium. Pyrene was selected as model compound from high molecular weight hydrocarbons recorded 84% and 78% degradation by the consortium at 50 ppm and 100 ppm in 8 and 10 days, respectively. The halophilic consortium revealed complete degradation of HD at 0.5% and 1% concentration under saline condition. The consortium was able to degrade 93% and 71% of HD at 1.5 and 2% concentration in 6 and 8 days under saline condition. Under different high saline conditions such as 8%, 12%, 16% and 20%, the halophilic consortium exhibited PHE (95%, 90%, 85%, 65%) and FLU (97%, 92%, 86%, 66%) degradation in 7, 10, 14 and 18 days. Addition of urea and yeast extract at high salinity enhanced the biomass production and reduced the time taken for degradation. The surface tension of the biosurfactant produced by the consortium was 36 ± 1 mN/m. The treatment of hydrocarbons-contaminated boat fuel station wastewater in continuous stirred tank reactor recorded 92% Chemical Oxygen Demand removal in 40 days. The potential halophilic strains present in the consortium responsible for petroleum hydrocarbon degradation were identified as Marinobacter, Rhodococcus, Ochrobactrum, Martelella, Pseudomonas, Stenotrophomonas and Sedimentibacter.

A Gram-stain-negative, moderately halophilic strain, designated strain L5T, was isolated from wetsalted hides collected from Chengdu, south-west PR China. The cells were motile, facultative aerobic, short rod-shaped and non-endospore-forming. Growth of strain L5T occurred at pH 6–10 (optimum, pH 8), 10–45 °C (optimum, 30 °C) and in the presence of 1–17 % (w/v) NaCl (optimum, 10 %). Results of phylogenetic analyses based on 16S rRNA, gyrB and rpoD gene sequences and its genome revealed that strain L5T belonged to the genus Halomonas . Strain L5T was found to be most closely related to the type strains of Halomonas saliphila , Halomonas lactosivorans , Halomonas kenyensis , Halomonas daqingensis and Halomonas desiderata (98.8, 98.6, 98.3, 97.9 and 97.4 % 16S rRNA gene sequence similarity, respectively). The draft genome was approximately 4.2 Mb in size with a G+C content of 63.5 mol%. The average nucleotide identity (ANI) and digital DNA–DNA hybridization values among strain L5T and the selected Halomonas species were 83.3–88.9 % (ANIm), 71.1–87.3 % (ANIb) and 20.2–34.6 %, which are below the recommended cutoff values. Major fatty acids were C16 : 0, C16 : 1 ω7c, C18 : 1 ω7c and C19 : 0 cyclo ω8c and the predominant ubiquinone was Q-9, with minor ubiquinone Q-8 also present. The phospholipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, four unidentified aminophospholipids and three unidentified phospholipids. Based on the mentioned polyphasic taxonomic evidence, strain L5T represents a novel species within the genus Halomonas , for which Halomonas pellis sp. nov. is proposed. The type strain is L5T (=CGMCC 1.17335T=KCTC 72573T).

Salinity is one of the most important growth-limiting factors for most crops in arid and semi-arid regions; however, the use of plant growth-promoting rhizobacteria isolated from saline soils could reduce the effects of saline stress in crops. This study aimed to evaluate the efficiency of plant growth-promoting rhizobacteria (PGPRs), isolated from the rhizosphere of halophile plants, for the growth, Na+/K+ balance, ethylene emission, and gene expression of wheat seedlings (Triticum aestivum L.) grown under saline conditions (100 mmol L−1 NaCl) for 14 d. A total of 118 isolates obtained from saline soils of the deserts of Iran were tested for their capacity as PGPRs. Out of the 118 isolates, 17 could solubilize phosphate (Ca3(PO4)2), 5 could produce siderophores, and 16 could synthesize indole-3-acetic acid. Additionally, PGPRs were also evaluated for aminocyclopropane-1-carboxylate deaminase activity. A pot experiment was conducted to evaluate the ability of 28 PGPR isolates to promote growth, regulate Na+/K+ balance, and decrease ethylene emissions in plants. The most efficient PGPRs were Arthrobacter aurescens, Bacillus atrophaeus, Enterobacter asburiae, and Pseudomonas fluorescens. Gene expression analysis revealed the up-regulation of H+-PPase, HKT1, NHX7, CAT, and APX expression in roots of Enterobacter-inoculated salt-stressed plants. Salt-tolerant rhizobacteria exhibiting plant growth-promoting traits can facilitate the growth of wheat plants under saline conditions. Our results indicate that the isolation of these bacteria may be useful for formulating new inoculants to improve wheat cropping systems in saline soils.

Jambal roti is a traditional salted-fermented product made from Arius thalassinus, which is a popular fish in Central Java Province, Indonesia. This research aimed to identify the moderate halophil...

The present study aimed to determine the degradation and transformation of three-ring PAHs phenanthrene and anthracene by Cryptococcus sp. MR22 and Halomonas sp. BR04 under halophilic conditions. The growth progress of Cryptococcus sp. MR22 and Halomonas sp. BR04 on anthracene and phenanthrene was monitored by colony-forming unit (CFU) technique. The growth of the bacteria was maintained at a maximum concentration of 200 mg/L of all tested hydrocarbon, indicating that Cryptococcus sp. MR22 and Halomonas sp. BR04 significantly perform in the removal of the PAH-contaminated medium at low concentrations. The fit model to represent the biodegradation kinetics of both PAHs was first-order rate equation The extract prepared from cells supplemented with three different substrates exhibited some enzymes such as hydroxylase, dioxygenase, laccase and peroxidase. The results suggest that both strains had an impressive ability in the degradation of aromatic and aliphatic hydrocarbon but also could tolerate in the extreme salinity condition.

An incubation experiment was conducted to examine combined or individual impacts of biochar and/or 3,4-dimethylpyrazole phosphate (DMPP) on the net nitrification rates, the abundances of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB, a halophilic β-AOB) and TAO100 (a non-halophilic γ-AOB), and comammox Nitrospira in a highly acidic sugarcane soil. The net nitrification rates were markedly suppressed by biochar and/or DMPP application. Urea addition stimulated but DMPP alone significantly inhibited the growth of AOB, TAO100, total comammox Nitrospira, and clade A. The application of biochar alone increased AOA and AOB abundances, but reduced those of TAO100, total comammox Nitrospira, and clade A. Likely in the combined biochar and DMPP treatment, DMPP was absorbed by biochar then reducing its efficacy in suppressing the growth of AOB, total comammox Nitrospira, and clade A. Total comammox Nitrospira and clade A abundances were significantly correlated with NO3− concentrations (P

A novel exopolysaccharide, designated hsEPS, was successfully prepared from the high-salt-fermented broth of a novel species Halomonas saliphila LCB169T by ethanol precipitation, anion-exchange and gel-filtration chromatography, and its structure was well-characterized by means of chemical and spectral analyses. Results showed that hsEPS was primarily composed of mannose and glucose with a relative weight-average molecular weight of 5.133 × 104 g/mol. It was deduced that the major backbone contained (1→2)-linked α-D-Manp and (1→6)-linked α-D-Manp with branches substituted at C-2 by T-α-D-Manp and at C-6 by the fragment of T-α-D-Manp-(1→2)-α-D-Manp-(1→. A sheet-like structure was observed under high magnification. The water solubility index, water holding capacity, oil holding capacity and foaming capacity of hsEPS were 98.0, 19.3, 1386.7 and 82.2%, respectively. It also exhibited outstanding emulsifying activity against all tested edible oils. Together, the resulted data indicated that hsEPS might serve as an active ingredient in food, cosmetics and detergents.

Phialosimplex asmahalo is an obligate halophilic fungus that requires at least 5 % (w/v) sodium chloride for growth. It was previously isolated and identified. The ethyl acetate extract ofPhialosimplex asmahalo was fractionated and three compounds 1, 3, and 6 were purified. In this studypure compounds of Phialosimplex asmahalo were evaluated for their anti-diabetes, anti-inflammatory, antiviral and hepatoprotective activities. Compounds 3 and 6 have anti-diabetic activities with IC50 47.03 and 82.3 respectively; whereas compound 1 has no anti-diabetic activity. Compounds 3 and 6 have anti-inflammatory activities with IC50 125 and 294 respectively; whereas compound 1 has no anti-inflammatory activity. Compound 3 has antiviral activity against Hepatitis A virus and Herpes Simplex type 1 virus in a percentage of 24.7 and 10.2 respectively. Compound 6 has antiviral activity against Hepatitis A only with a percentage of 11.3. Compound 1 has no antiviral activity against Hepatitis A virus and Herpes Simplex type 1 virus. Compounds 1 and 3 have hepatoprotective activities percentage 7.1 and 23.6 respectively; whereas compound 6 has no hepatoprotective activity.

The compatible solutes ectoine and hydroxyectoine are synthesized by many microorganisms as potent osmostress and desiccation protectants. Besides their successful implementation into various skincare products, they are of increasing biotechnological interest due to new applications in the healthcare sector. To meet this growing demand, efficient heterologous overproduction solutions for ectoines need to be found. This study is the first report on the utilization of the non-halophilic biosynthesis enzymes from Acidiphilium cryptum DSM 2389T for efficient heterologous production of ectoines in Escherichia coli. When grown at low salt conditions (≤ 0.5% NaCl) and utilizing the cheap carbon source glycerol, the production was characterized by the highest specific production of ectoine [2.9 g/g dry cell weight (dcw)] and hydroxyectoine (2.2 g/g dcw) reported so far and occurred at rapid specific production rates of up to 345 mg/(g dcw × h). This efficiency in production was related to an unprecedented carbon source conversion rate of approx. 60% of the theoretical maximum. These findings confirm the unique potential of the here implemented non-halophilic enzymes for ectoine production processes in E. coli and demonstrate the first efficient heterologous solution for hydroxyectoine production, as well as an extraordinary efficient low-salt ectoine production. Electronic supplementary material The online version of this article (10.1007/s00792-020-01188-8) contains supplementary material, which is available to authorized users.

A moderately halophilic strain, designated SCU50T, was recovered from a saline soil sample and characterized by a polyphasic approach. The 16S rRNA gene sequence analysis showed that strain SCU50T belonged to the genus Gracilibacillus and was most closely related to Gracilibacillus thailandensis TP2-8T (98.1 % similarity) and Gracilibacillus orientalis XH-63T (97.7 %). Genomic average nucleotide identity and digital DNA–DNA hybridization analyses confirmed the separate species status of the new isolate relative to other recognized Gracilibacillus species. The genome size was about 5.09 Mbp and the DNA G+C content was 36.7 mol%. The strain grew optimally at 10–15 % (w/v) NaCl, pH 6.5–7.5 and 25–30 °C. It contained anteiso-C15 : 0, iso-C15 : 0 and anteiso-C17 : 0 as the dominant fatty acids and menaquinone-7 as the major respiratory quinone. The polar lipid profile was examined and found to comprise diphosphatidylglycerol, phosphatidylglycerol, one unidentified phospholipid and one unidentified lipid. The cell-wall peptidoglycan type was A1γ based on meso-diaminopimelic acid. Combining the data from phenotypic, chemotaxonomic, genomic and phylogenetic characterization, it was concluded that strain SCU50T should be assigned as representing a novel species within the genus Gracilibacillus . Thus, a novel taxon named Gracilibacillus salitolerans sp. nov. was first established, with SCU50T (=CGMCC 1.17336T=KCTC 43107T) as the type strain.

A novel archaeal strain designated as SPP-AMP-1T was isolated from saltpan soil, using the serial dilution method on a halophilic archaeal medium supplemented with ampicillin. Cells were both rod-shaped and pleomorphic in nature, non-motile, unable to produce acid from a variety of sugars or grow anaerobically with different substrates (l-arginine) and electron acceptors (DMSO, nitrate). Optimal growth was observed at 42 °C, 3.4–4.2 M NaCl and pH 7.2. Cells did not lyse in distilled water and grew in the absence of Mg2+ ions. Phylogenetic analysis based on the sequences of 16S rRNA gene, amino acid sequence of β′-subunit of RNA polymerase and 400 conserved proteins retrieved from the whole genome assemblies showed that strain SPP-AMP-1T was distantly related to any existing genera within the family Halobacteriaceae . MK-8 was the only quinone detected. Polar lipid analysis showed a unique combination of diethyl derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, glycosyl-mannosyl-glucosyl diether and sulphated glycosyl-mannosyl-glucosyl diether as the major lipids. The G+C content of genomic DNA is 57.7 mol%. The phenotypic, phylogenetic and genomic data supported the concept of the novel genus status of strain SPP-AMP-1T in the family Halobacteriaceae for which the name Halocatena pleomorpha gen. nov., sp. nov., is proposed; the type strain is SPP-AMP-1T (=JCM 31368T=KCTC 4276T=MTCC 12579T).

The salt-tolerant unicellular alga Dunaliella bardawil FACHB-847 can accumulate large amounts of lutein, but the underlying cause of massive accumulation of lutein is still unknown. In this study, genes encoding two types of carotene hydroxylases, i.e., β-carotene hydroxylase (DbBCH) and cytochrome P450 carotenoid hydroxylase (DbCYP97s; DbCYP97A, DbCYP97B, and DbCYP97C), were cloned from D. bardawil. Their substrate specificities and enzyme activities were tested through functional complementation assays in Escherichia coli. It was showed that DbBCH could catalyze the hydroxylation of the β-rings of both β- and α-carotene, and displayed a low level of e-hydroxylase. Unlike CYP97A from higher plants, DbCYP97A could not hydroxylate β-carotene. DbCYP97A and DbCYP97C showed high hydroxylase activity toward the β-ring and e-ring of α-carotene, respectively. DbCYP97B displayed minor activity toward the β-ring of α-carotene. The high accumulation of lutein in D. bardawil may be due to the multiple pathways for lutein biosynthesis generated from α-carotene with zeinoxanthin or α-cryptoxanthin as intermediates by DbBCH and DbCYP97s. Taken together, this study provides insights for understanding the underlying reason for high production of lutein in the halophilic green alga D. bardawil FACHB-847.

In the current study, the PGP (production of siderophore and IAA, fixation of nitrogen and solubilization of phosphate) potential of forty-five bacterial isolates comprising sixteen genera (Marinibacillus, Zhihengliuella, Bacillus, Nesterenkonia, Halobacillus, Promicromonospora, Terribacillus, Jeotgalibacillus, Staphylococcus, Oceanobacillus, Virgibacillus, Halomonas, Gracilibacillus, Planococcus, Thalassobacillus and Microbacterium) was investigated. Among these forty-five bacterial isolates, most of the isolates (40 isolates) possess plant growth promoting potential. Four bacterial isolates [Marinibacillus sp. (EM1), Zhihengliuella salsuginis (EM30), Planococcus sp. (EK9), and Promicromonospora sp. (EK12)] possessing PGP traits were applied on the barley grown under salt (NaCl) stress in a hydroponic system. Comparing to the un-inoculated group, all the four bacterial isolates significantly improved plant growth that inhibited with NaCl (200 mM) stress. The growth rate of the plants inoculated with Zhihengliuella salsuginis (EM30), Promicromonospora sp. (EK12), Planococcus sp. (EK9), and Marinibacillus sp. (EM1) was 81.86, 80.51, 70.62 and 69.22, respectively. As far as we know, this is the first report showing the PGP potential of Marinibacillus sp. (EM1), Bacillus horikoshii (EM9), Bacillus patagoniensis (EM12), Bacillus agaradhaerens (EK13), Oceanobacillus profundus (EM26) Thalassobacillus devorans (EM34) and Promicromonospora sp. (EK12).

An aerobic, Gram-stain-negative ovoid, designated as strain A21T, was isolated using the dilution-to-extinction method from a soil sample taken from Rambla Salada, an athalassohaline habitat located in Murcia (south-eastern Spain). Strain A21T is non-motile, has a respiratory metabolism and grows at NaCl concentrations within the range 0.5–15 % (w/v) [optimum, 5 % (w/v)], at 5–35 °C (optimum, 28 °C) and at pH 6–8 (optimum, pH 7.0). This strain is positive for catalase activity, oxidase activity and nitrate reduction. The 16S rRNA gene sequence indicates that it belongs to the genus Roseovarius in the class Alphaproteobacteria . The most closely related species are Roseovarius pacificus and Roseovarius halotolerans to which the strain A21T shows 16S rRNA gene sequence similarity values of 98.06 and 97.7 %, respectively. The average nucleotide identity in blast and digital DNA–DNA hybridization values between strain A21T and R. pacificus LMG 24575T are 76.8 and 21 %, respectively. The DNA G+C content based on the genome is 61.28 mol%. The major fatty acids (>5 % of the total fatty acids) of strain A21T are C18 : 1 ω7c/C18 : 1 ω6c and C16 : 0. The only detected isoprenoid quinone in strain A21T is ubiquinone 10 (Q-10). The polar lipid profile contains phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and three unidentified polar lipids. Based on the phylogenetic, genotypic, phenotypic and chemotaxonomic data, the strain represents a novel species of the genus Roseovarius , for which the name Roseovarius bejariae sp. nov. is proposed. Strain A21T (=CECT 9817T=LMG 31311T) is the type strain.

In the course of screening halophilic bacteria in Urmia Lake in Iran, which is being threatened by dryness, a novel Gram-negative, moderately halophilic, heterotrophic and short rod-shaped bacteria was isolated and characterized. The bacterium was isolated from a water specimen and designated as TBZ3T. Colonies were found to be creamy yellow, with catalase- and oxidase-positive activities. The growth of strain TBZ3T was observed to be at 10–45 °C (optimum, 30 °C), at pH 6.0–9.0 (optimum, pH 7.0) and in the presence of 0.5–20 % (w/v) NaCl (optimum, 7.5 %). Strain TBZ3T contained C16 : 0, cyclo-C19 : 0 ω8c, summed feature 3 (comprising C16 : 1 ω7c and/or C16 : 1 ω6c) and summed feature 8 (comprising C18 : 1 ω7c and/or C18 : 1 ω6c) as major fatty acids and ubiquinone-9 as the only respiratory isoprenoid quinone. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, glycolipid, unidentified phospholipid and unidentified polar lipids were detected as the major polar lipids. Strain TBZ3T was found to be most closely related to Halomonas saccharevitans AJ275T , Halomonas denitrificans M29T and Halomonas sediminicola CPS11T with the 16S rRNA gene sequence similarities of 98.93, 98.15 and 97.60 % respectively and in phylogenetic analysis strain TBZ3T grouped with Halomonas saccharevitans AJ275T contained within a large cluster within the genus Halomonas . Based on phenotypic, chemotaxonomic and molecular properties, strain TBZ3T represents a novel species of the Halomonas genus, for which the name Halomonas urmiana sp. nov. is proposed. The type strain is TBZ3T (=DSM 22871T=LMG 25416T).

The present study was conducted to reveal specific bacterial consortium belong to same genus capable of mineralizing petroleum hydrocarbons and also act as a valid indicator to locate the oil reser...

Three halophilic archaeal strains, YJ-53T, ZS-5 and DYF38, were isolated from marine solar salterns located in different provinces of China. The three strains formed a single cluster (99.7–99.8 and 97.9–99.2 % similarities, respectively) that was separate from the current two members of Salinigranum (96.7–98.0 and 89.8–92.9 % similarities, respectively) on the basis of 16S rRNA and rpoB′ gene sequence comparisons and phylogenetic analysis. Diverse phenotypic characteristics differentiated strains YJ-53T, ZS-5 and DYF38 from Salinigranum rubrum GX10T and Salinigranum salinum YJ-50-S2T. The major polar lipids of isolated strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and two major glycolipids chromatographically identical to mannosyl glucosyl diether and sulfated mannosyl glucosyl diether, detected in the current members of Salinigranum . The OrthoANI and in silico DNA–DNA hybridization (DDH) values between the three strains were in the range of 97.7–98.4 % and 80.3–86.1 %, respectively, much higher than the threshold values proposed as species boundaries (average nucleotide identity 95–96 % and in silico DDH 70 %), revealing that the three strains represent one species. Results of comparative OrthoANI and in silico DDH analyses of the strains described in this study with validly described members of the genus Salinigranum supported that strains YJ-53T (=CGMCC 1.12860T=JCM 30238T), ZS-5 (=CGMCC 1.12867=JCM 30240) and DYF38 (=CGMCC 1.13779=JCM 33557) represent a novel species of the genus Salinigranum , for which the name Salinigranum halophilum sp. nov. is proposed.

Marine macroalgae have gained considerable attention as renewable biomass sources. Ulvan is a water-soluble anionic polysaccharide, and its depolymerization into fermentable monosaccharides has great potential for the production of bioethanol or high-value food additives. Ulvan lyase from Alteromonas sp. (AsPL) utilizes a β-elimination mechanism to cleave the glycosidic bond between rhamnose 3-sulfate and glucuronic acid, forming an unsaturated uronic acid at the non-reducing end. AsPL was active in the temperature range of 30–50 °C and pH values ranging from 7.5 to 9.5. Furthermore, AsPL was found to be halophilic, showing high activity and stability in the presence of up to 2.5 M NaCl. The apparent Km and kcat values of AsPL are 3.19 ± 0.37 mg mL−1 and 4.19 ± 0.21 s−1, respectively. Crystal structure analysis revealed that AsPL adopts a β-propeller fold with four anti-parallel β-strands in each of the seven propeller blades. The acid residues at the protein surface and two Ca2+ coordination sites contribute to its salt tolerance. The research on ulvan lyase has potential commercial value in the utilization of algal resources for biofuel production to relieve the environmental burden of petrochemicals.

Three rod-shaped halophilic archaeal strains, DL-M4T, LYG-109 and DLLS-108T, were isolated from the salted brown alga Laminaria produced in different marine areas of PR China. Cells of strains were motile, formed red-pigmented colonies on agar and lysed in distilled water. The three strains grew optimally with 2.6 M NaCl, with 0.05–0.3 M MgCl2, at 37 °C and at pH 7.0–7.5. The results of phylogenetic analyses based on the 16S rRNA and rpoB′ genes differentiated these strains into two clusters belonging to the genus Halostella , which currently contains Halostella salina CBA1114T and Halostella limicola LT12T. Strains DL-M4T and LYG-109 formed a single cluster separate from the current two members of Halostella (94.4–95.7 and 90.0–90.9 % similarities, respectively) while strain DLLS-108T had Hsl. salina CBA1114T as its nearest neighbour (97.7–97.8 and 95.9 % similarities, respectively) and was separated from Hsl. limicola LT12T (94.4–95.8 and 93.4 % similarities, respectively). These clusters represented two distinct novel species as indicated by phenotypic characteristics, polar lipid compositions and whole-genome comparisons. Diverse phenotypic characteristics, morphology and growth characteristics, nutrition and miscellaneous biochemical tests differentiate strains DL-M4T, LYG-109, DLLS-108T from Hsl. limicola LT12T and Hsl. salina CBA1114T. Strains DL-M4T and LYG-109 contained phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and three unidentified glycolipids, while strain DLLS-108T contained these polar lipids and two unidentified phospholipids. The major respiratory quinones detected in the three isolates were menaquinone MK-8 and MK-8(H2). The average nucleotide identity (ANI) and in silico DNA–DNA hybridization (isDDH) values between the isolated strains and the current two members of Halostella were found to be 79.3–86.6 (ANI) and 22.9–49.8 % (isDDH). All these results showed that the three isolates represent two novel species of the genus Halostella for which the names Halostella pelagica sp. nov. [type strain dl-M4T (=CGMCC 1.13603T=JCM 32954T)] and Halostella litorea sp. nov. [type strain DLLS-108T(=CGMCC 1.13610T=JCM 32955T)] are proposed.

A Gram-stain-positive, moderately halophilic, strictly aerobic, endospore-forming, rod-shaped bacterium, strain JSM 102062T, was isolated from a non-saline farm soil sample collected from Dehang Canyon in Hunan, PR China. Growth occurred with 0.5–20 % (w/v) NaCl (optimum 4–7 %) at pH 5.5–11.0 (optimum pH 8.0) and at 20–50 °C (optimum 30–35 °C). Contained cell-wall peptidoglycan based on meso-diaminopimelic acid and possessed menaquinone-7 (MK-7) as the major respiratory isoprenoid quinone. The major cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The polar lipid pattern consisted of diphosphatidylglycerol, phosphatidylglycerol, five unidentified phospholipids and an unidentified glycolipid. The DNA G+C content was 44.1 mol%. Phylogeny based on 16S rRNA gene sequences indicated that strain JSM 102062T belonged to the genus Sediminibacillus , sharing high 16S rRNA gene sequence similarities to Sediminibacillus halophilus EN8dT (99.4 %) and Sediminibacillus albus NHBX5T (98.3 %). The whole genomic analysis showed that strain JSM 102062T constituted a different taxon separated from the recognized Sediminibacillus species. Combined data from phenotypic and genotypic studies demonstrated that strain JSM 102062T represents a noval species of the genus Sediminibacillus , for which the name Sediminibacillus terrae sp. nov. is proposed; the type strain is JSM 102062T (=CCTCC AB 2014166T = CGMCC 1.12957T=DSM 28949T=KCTC 33541T).

An aerobic, Gram-stain-positive, endospore-forming, rod-shaped and moderately halophilic strain SKP4-6T, was isolated from shrimp paste (Ka-pi) collected from Samut Sakhon Province, Thailand. Phylogenetic analysis revealed that strain SKP4-6T belonged to the genus Halobacillus and was most closely related to Halobacillus salinus JCM 11546T (98.6 %), Halobacillus locisalis KCTC 3788T (98.6 %) and Halobacillus yeomjeoni KCTC 3957T (98.6 %) based on 16S rRNA gene sequence similarity. The digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain SKP4-6T and its related species were 18.2–19.3 % and 69.84–84.51 %, respectively, which were lower than the threshold recommended for species delineation. The strain grew optimally at 30–40 °C, at pH 7.0 and with 10–15 % (w/v) NaCl. It contained l-Orn–d-Asp in the cell wall peptidoglycan. The DNA G+C content was 44.8 mol%. The major fatty acids were iso-C15 : 0, anteiso-C15 : 0 and anteiso-C17 : 0. The predominant isoprenoid quinone was MK-7. Phosphatidylglycerol and diphosphatidylglycerol were present as major polar lipids. Based on this polyphasic approach, digital DNA–DNA relatedness and ANI values, strain SKP4-6T represents a novel species of the genus Halobacillus , for which the name Halobacillus fulvus sp. nov. is proposed. The type strain is SKP4-6T (=JCM 32624T=TISTR 2595T).

Actinomycetes are versatile about their metabolism, displaying high capacity to produce bioactive metabolites. Enzymes from actinomycetes represent new opportunities for industrial applications. However, proteases from actinomycetes are poorly described by literature. Thereby, to verify proteolytic potential of actinomycetes, the present study aimed the investigation of bacterial isolates from Caatinga and Atlantic Forest rhizosphere. Fluorescence Resonance Energy Transfer (FRET) peptide libraries were adopted for the evaluations, since they are faster and more qualitative methods, if compared to others described by most reports. A total of 52 microorganisms were inoculated in different culture media (PMB, PDA, BHI, SCA and R2A), temperatures (12, 20, 30, 37, 45 and 60 °C), and saline conditions (0 to 4 M NaCl), during 7 days. The actinomycetes named as AC 01, 02 and 52 were selected and show enzymatic abilities under the peptide probes Abz-KLRSSKQ-EDDnp and Abz-KLYSSKQ-EDDnp, achieving enhanced performance at 30 °C. Biochemical parameters were established, showing a predominance of alkaline proteases with activity under saline conditions. Secreted proteases hydrolyzed preferentially polar uncharged residues (Y and N) and positively charged groups (R). PMSF and EDTA inhibited the proteins, a characteristic of serine (AC 01 e 02) and metalloproteases (AC 52). All selected strains belonged to Streptomyces genera. In summary, actinomycete strains with halophilic proteolytic abilities were selected, which improve possibilities for their use in detergent formulations, food processing, waste management and industrial bioconversion. It is important to highlight that this is the first report using FRET libraries for proteolytic screening from Caatinga and Atlantic Forest actinobacteria.

Strains of Dunaliella salina microalgae are of considerable research and industrial interest because they hyper-accumulate β-carotene as well as produce high-quality protein. To explore the co-production of valuable compounds in D. salina, this study compared the production of β-carotene, phytoene and amino acids in two strains cultivated under white, red or blue light until no further nitrogen was available. D. salina DF15 (CCAP 19/41 (PLY DF15)) produced more than 12% β-carotene (ash-free dry weight (AFDW) basis), and red light triggered the production of 9-cis β-carotene at a 9-cis/all-trans β-carotene ratio of 1.5. Phytoene production was also evident in D. salina DF15 under all conditions, particularly under blue light. However, the profile of essential amino acids (EAAs) and calculation of the essential amino acid index (EAAI) was less than ideal in terms of protein quality, for both strains. Umami compounds, quantified as monosodium glutamate (MSG) equivalents, indicated a higher equivalent umami concentration (EUC) in D. salina DF15 under red light (3.2 g MSG/100 g AFDW) than in D. salina CCAP19/30. Overall, D. salina DF15 demonstrates valuable traits for further exploration and product optimisation.

The chlorophyll ethanol-extracted silkworm excrement was hardly biologically reused or fermented by most microorganisms. However, partial extremely environmental halophiles were reported to be able to utilize a variety of inexpensive carbon sources to accumulate polyhydroxyalkanoates. In this study, by using the nile red staining and gas chromatography assays, two endogenous haloarchaea strains: Haloarcula hispanica A85 and Natrinema altunense A112 of silkworm excrement were shown to accumulate poly(3-hydroxybutyrate) up to 0.23 g/L and 0.08 g/L, respectively, when using the silkworm excrement as the sole carbon source. The PHA production of two haloarchaea showed no significant decreases in the silkworm excrement medium without being sterilized compared to that of the sterilized medium. Meanwhile, the CFU experiments revealed that there were more than 60% target PHAs producing haloarchaea cells at the time of the highest PHAs production, and the addition of 0.5% glucose into the open fermentation medium can largely increase both the ratio of target haloarchaea cells (to nearly 100%) and the production of PHAs. In conclusion, our study demonstrated the feasibility of using endogenous haloarchaea to utilize waste silkworm excrement, effectively. The introduce of halophiles could provide a potential way for open fermentation to further lower the cost of the production of PHAs.

Rhodothermus marinus is a halophilic extreme thermophile, with potential as a model organism for studies of the structural basis of antibiotic resistance. In order to facilitate genetic studies of this organism, we have surveyed the antibiotic sensitivity spectrum of R. marinus and identified spontaneous antibiotic-resistant mutants. R. marinus is naturally insensitive to aminoglycosides, aminocylitols and tuberactinomycins that target the 30S ribosomal subunit, but is sensitive to all 50S ribosomal subunit-targeting antibiotics examined, including macrolides, lincosamides, streptogramin B, chloramphenicol, and thiostrepton. It is also sensitive to kirromycin and fusidic acid, which target protein synthesis factors. It is sensitive to rifampicin (RNA polymerase inhibitor) and to the fluoroquinolones ofloxacin and ciprofloxacin (DNA gyrase inhibitors), but insensitive to nalidixic acid. Drug-resistant mutants were identified using rifampicin, thiostrepton, erythromycin, spiramycin, tylosin, lincomycin, and chloramphenicol. The majority of these were found to have mutations that are similar or identical to those previously found in other species, while several novel mutations were identified. This study provides potential selectable markers for genetic manipulations and demonstrates the feasibility of using R. marinus as a model system for studies of ribosome and RNA polymerase structure, function, and evolution.

Histones, ubiquitous in eukaryotes as DNA-packing proteins, find their evolutionary origins in archaea. Unlike the characterized histone proteins of a number of methanogenic and themophilic archaea, previous research indicated that HpyA, the sole histone encoded in the model halophile Halobacterium salinarum, is not involved in DNA packaging. Instead, it was found to have widespread but subtle effects on gene expression and to maintain wild type cell morphology; however, its precise function remains unclear. Here we use quantitative phenotyping, genetics, and functional genomic to investigate HpyA function. These experiments revealed that HpyA is important for growth and rod-shaped morphology in reduced salinity. HpyA preferentially binds DNA at discrete genomic sites under low salt to regulate expression of ion uptake, particularly iron. HpyA also globally but indirectly activates other ion uptake and nucleotide biosynthesis pathways in a salt-dependent manner. Taken together, these results demonstrate an alternative function for an archaeal histone-like protein as a transcriptional regulator, with its function tuned to the physiological stressors of the hypersaline environment.

(1) Background: this study describes bioactive compounds in the following halophytes: Sarcocornia (S. alpini, S. pruinosa, and S. perennis) and Arthrocnemum (A. macrostachyum). The material comes from: coastal marshes in Tinto River, Guadiana River, and some interior provinces from the Iberian Peninsula. (2) Methods: the techniques used were Folin–Ciocalteu, GC-MS, and ESI-MS/MS. (3) Results: Five phenolic acids were found in Sarcocornia: trans-cinnamic, salicylic, veratric, coumaric, and caffeic acids. In addition, in Arthronemum, ferulic acid was also detected. The obtained flavonoids were cyanidin-3-O-arabinoside, luteolin-7-glucoside, dihydroquercetin, and p-coumaroyl-glucoside. They also presented fatty acids, such as palmitic, linoleic, and oleic acids in Sarcocornia, while palmitic, linolenic, and stearic acids were the main fatty acids in A. macrostachyum. (4) Conclusions: the high diversity of the compounds identified confirms the relation between nutritional interest and salt tolerance in halophytes.

Vibrio alginolyticus is a halophilic organism usually found in marine environments. It has attracted attention as an opportunistic pathogen of aquatic animals and humans, but there are very few reports on polyhydroxyalkanoate (PHA) production using V. alginolyticus as the host. In this study, two V. alginolyticus strains, LHF01 and LHF02, isolated from water samples collected from salt fields were found to produce poly(3-hydroxybutyrate) (PHB) from a variety of sugars and organic acids. Glycerol was the best carbon source and yielded the highest PHB titer in both strains. Further optimization of the NaCl concentration and culture temperature improved the PHB titer from 1.87 to 5.08 g/L in V. alginolyticus LHF01. In addition, the use of propionate as a secondary carbon source resulted in the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). V. alginolyticus LHF01 may be a promising host for PHA production using cheap waste glycerol from biodiesel refining.

Screening of halophilic and halotolerant bacteria isolated from biocenoses of the industrial development area of the Verkhnekamsk potassium-magnesium salt deposit (Perm krai) for the ability to synthesize a biotechnologically significant osmoprotector - ectoine was carried out. For the study, representatives of the genera Halomonas and Chromohalobacter of the Halomonadaceae family of the Gammaproteobacteria class, as well as strains of bacteria belonging to the genera Arthrobacter and Rhodococcus of the Actinobacteria class were selected from the working collection of microorganisms of the Laboratory of Molecular Microbiology and Biotechnology of the «Institute of Ecology and Genetics of Microorganisms (Russian Academy of Science, Ural Branch)». In the course of 'Н NMR spectroscopy studies, ectoine was shown to predominate in the cells of the Halomonadaceae family: its proportion, depending on the strain, was 64,0-78,1%. Structural and functional analysis of genes encoding ectoine synthesis enzymes was carried out in the genomes of bacteria of the genera Halomonas, Chromohalobacter, Cobetia, Kushneria, Halotalea and Salinicola of the Halomonadaceae family, deposited in the public database of the National Center for Biotechnological Information of the United States (NCBI). A protocol for amplification of the ect-genes in bacteria of the studied taxonomic groups was developed and tested.

The halophilic bacterium Pseudoalteromonas phenolica is well known as a promising candidate that enables the recycling of organic wastes at high salinity. However, for industrial applications of P. phenolica further research is required to explore the biological mechanism for maximizing the activities and productivities of this bacterium. In this study, we investigated the osmotic stress resistance and specific protease activities of P. phenolica in a normal-salt medium (0.3 M NaCl) and high-salt medium (1 M NaCl) based on intra- and extracellular multi-omics approaches. Proteins related to betaine and proline biosynthesis were increased under high salt stress. The targeted metabolite analysis found that proline was overproduced and accumulated outside the cell at high salinity, and betaine was accumulated in the cell by activation of biosynthesis as well as uptake. In addition, extracellular serine proteases were shown to be upregulated in response to salt stress by the extracellular proteomic analysis. The specific proteolytic activity assay indicated that the activities of serine proteases, useful enzymes for the recycling of organic wastes, were increased remarkably under high salt stress. Our results suggest that betaine and proline are key osmoprotectant metabolites of P. phenolica, and they can be used for the improvement of protease production and P. phenolica activities for the recycling of high-salt organic wastes in the future.

Conventionally, animal hide and skin necessitates 95% saturated brine solution (SBS) for its preservation. This salt is primarily derived from different sources including solar-saltern, evaporation ponds, etc., which are laden with different types of halophilic micro-organisms. Previous studies confirmed that the presence of moderately halophilic bacteria caused red heat on cured hide, which adversely affects the leather quality and causes substantial economic losses for leather industries. Thus, this investigation was carried out to examine the effects of different concentrations of alkyltrimethylammonium bromide (ATMB) on selected halophilic-bacteria attributed to the deterioration of hide quality. In nutrient broth solution (NBS), ATMB at 250 and 500 ppm reduced individual halo-bacteria, that is, Halomonas halodenitrificans, Halomonas eurihalina, Alkalibacillus haloalkaliphilus and Salimicrobium album, by averages of 0·64 and 1·90, 1·5 and 2·61, 0·90 and 2·27, 1·65 and 3·36 log CFU per ml respectively in 5 min. ATMB treatment in SBS at 500 ppm for 18 h resulted in a reduction of H. halodenitrificans, H. eurihalina, A. haloalkaliphilus and S. album by averages of 1·9, 1·25, 0·96 and 1·34 log CFU per ml respectively, when compared with the controls. Likewise, 5000 ppm ATMB reduced the cocktail population nearly to zero from that cultivated in SBS for 18 h. SIGNIFICANCE AND IMPACT OF THE STUDY: In this investigation, the inhibition of different halophilic bacteria that causes red heat in salt-preserved hides is described for the first time. The antimicrobial susceptibility test executed via solution procedures for selected halophilic bacterial strains (i.e. resistant to the salt environment) revealed significant efficacy of alkyltrimethylammonium bromide (ATMB). The current study suggests that, chemical compound like ATMB could be utilized to prevent red heat-related damage on salt-cured hides caused by halophilic bacteria, which is a persisting concern of the leather industry.

Thiocyanate (SCN-) is harmful to a wide range of organisms, and its removal is essential for environmental protection. A neutrophilic halophile capable of thiocyanate degradation, Thiohalobacter sp. strain FOKN1, was highly enriched (relative abundance; 98.4%) from activated sludge collected from a bioreactor receiving thiocyanate-rich wastewater. The enrichment culture degraded 3.38 mM thiocyanate within 140 h, with maximum activity at pH 8.8, 37°C, and 0.18 M sodium chloride. Thiocyanate degradation was inhibited by 30 mg L-1 phenol, but not by thiosulfate. Microbial thiocyanate degradation is catalyzed by thiocyanate dehydrogenase, while limited information is currently available on the molecular mechanisms underlying thiocyanate degradation by the thiocyanate dehydrogenase of neutrophilic halophiles. Therefore, (meta)genomic and proteomic analyses of enrichment cultures were performed to elucidate the whole genome sequence and proteome of Thiohalobacter sp. strain FOKN1. The 3.23-Mb circular Thiohalobacter sp. strain FOKN1 genome was elucidated using a PacBio RSII sequencer, and the expression of 914 proteins was identified by tandem mass spectrometry. The Thiohalobacter sp. strain FOKN1 genome had a gene encoding thiocyanate dehydrogenase, which was abundant in the proteome, suggesting that thiocyanate is degraded by thiocyanate dehydrogenase to sulfur and cyanate. The sulfur formed may be oxidized to sulfate by the sequential oxidation reactions of dissimilatory sulfite reductase, adenosine-5'-phosphosulfate reductase, and dissimilatory ATP sulfurylase. Although the Thiohalobacter sp. strain FOKN1 genome carried a gene encoding cyanate lyase, its protein expression was not detectable. The present study advances the understanding of the molecular mechanisms underlying thiocyanate degradation by the thiocyanate dehydrogenase of neutrophilic halophiles.

A halophilic bacterial strain, EG1HP4QL, was isolated from a salt sample from Lake Qarun, Fayoum Province, Egypt. Morphological, physiological, biochemical, and phylogenetic analyses indicated that the strain belonged to the genus Halobacillus. Strain EG1HP4QL produced an extracellular polysaccharide (EPS), with production peaking (5.9 g L−1) during growth on medium S-G containing 2% (w/v) sucrose at 35 °C (pH 8.0). The EPS had significant emulsifying activity (E24 %) against kerosene (65.7 ± 0.8%), o-xylene (64.0 ± 1%), and sunflower oil (44.7 ± 0.5%). The composition of the EPS included two polymers—a negatively charged and a neutral one (~ 3:1)—in which mannose and glucose were the main neutral monosaccharide constituents. Strain EG1HP4QL was able to utilize crude oil (35.3%) as the sole carbon source within 12 days. The minimum inhibitory concentrations of heavy metals [Zn(II), Cd(II), Pb(II), Ni(II), and Cu(II)] for strain EG1HP4QL were 1.0, 2.0, 2.0, 2.5, and 5 mM, respectively.

Present study aimed to evaluate culturable halophilic archaeal diversity of iodised crystal salt, obtained from the solar salterns of Vedaranyam, Tamil Nadu, India. Bright yellow-orange-red pigmented colonies were obtained, by surface spreading of the saturated salt crystal suspension, on complex media such as NTYE (NaCl Tryptone Yeast Extract) and EHM (Extremely Halophilic Medium), followed by incubating the plates for 30–45 days. The viable halophilic pigmented/non-pigmented microbial counts were determined as colony forming units (CFU/g), which were ~1.1 × 104/5.5 × 103 and ~1.0 × 104/4.0 × 103 on NTYE and EHM, respectively. Six morphologically distinct isolates were purified and identified. Morphological characteristics of the isolates revealed the cells to be cocci and involuted/cup shape, whereas chemotaxonomic characteristics revealed the presence of bacterioruberin pigment. Small subunit ribosomal RNA (16S rRNA) gene analysis revealed that, majority of the isolates belonged to genus Halococcus, except one belonged to genus Halorubrum. To the best of our knowledge, this is the first study reporting, prevalence of Halococcus in iodised crystal salt, of Vedaranyam, Tamil Nadu, India.

A Gram-stain-positive, aerobic, spore-forming, moderately halophilic bacterium, SSKP1-9T, was isolated from traditional salted shrimp paste (Ka-pi) produced in Samut Sakhon Province, Thailand. This strain grew optimally at 37–40 °C, pH 7.0 and in the presence of 8–16 % (w/v) NaCl. The 16S rRNA gene sequence similarity values between strain SSKP1-9T and Lentibacillus juripiscarius TISTR 1535T and Lentibacillus halophilus TISTR 1549T were 98.7 and 97.2 %, respectively. Based on 16S rRNA gene sequence similarity, strain SSKP1-9T represents a distinct novel species, as shown by phenotypic traits, DNA–DNA hybridization and average nucleotide identity values. In addition, the whole-cell protein profile confirmed the novelty of the taxon. The genomic DNA G+C content was 44.6 mol%. The major isoprenoid quinone was MK-7. The cell-wall peptidoglycan contained meso-diaminopimelic acid. Polar lipid analysis revealed the presence of phosphatidylglycerol, diphosphatidylglycerol, four unidentified lipids, an unidentified phospholipid and an unidentified glycolipid. The major cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The results of phenotypic and chemotaxonomic characteristics and whole-genome analysis support that strain SSKP1-9T represents a novel species of Lentibacillus , for which the name Lentibacilluslipolyticus sp. nov. is proposed. The type strain is SSKP1-9T (=JCM 32625T=TISTR 2597T).

Ectoine is an osmoprotector that is synthesized by many halophilic and halotolerant bacteria in response to osmotic stress. The halotolerant methanotroph Methylomicrobium alcaliphilum 20Z was genetically modified to produce ectoine derivative hydroxyectoine by introduction of the gene encoding ectoine hydroxylase EctD from Pseudomonas stutzeri DSM5190T. In the cells of the methanotroph transformed by the plasmid pMHA200 carrying ectD under control of either constitutive Pmxa promoter of methanol dehydrogenase or Pect promoter of the native ectABCask operon, most of intracellular ectoine was converted to hydroxyectoine. Cells of the methanotroph expressing the chromosomally located ectD gene accumulated ectoine and hydroxyectoine in almost equal ratio. Here we first showed that M. alcaliphilum 20Z can be appropriate strain to design hydroxyectoine producer from methane or methanol.