Molar Salt Concentrations Research Articles

Systematic Incorporation of Ionic Hard-Core Size into the Debye-Hückel Theory via the Cumulant Expansion of the Schwinger-Dyson Equations.

The Debye-Hückel (DH) formalism of bulk electrolytes equivalent to the Gaussian-level closure of the electrostatic Schwinger-Dyson identities without the interionic hard-core (HC) coupling is extended via the cumulant treatment of these equations augmented by HC interactions. By comparing the monovalent ion activity and pressure predictions of our cumulant-corrected DH (CCDH) theory with hypernetted-chain results and Monte Carlo simulations from the literature, we show that this rectification extends the accuracy of the DH formalism from submolar to molar salt concentrations. In the case of internal energies or the general case of divalent electrolytes mainly governed by charge correlations, the improved accuracy of the CCDH theory is limited to submolar ion concentrations. Comparison with experimental data from the literature shows that, via the adjustment of the hydrated ion radii, CCDH formalism can equally reproduce the nonuniform effect of salt increment on the ionic activity coefficients up to molar concentrations. The inequality satisfied by these HC sizes coincides with the cationic branch of the Hofmeister series.

Enhancement of Visible Light Antibacterial Activities of Cellulose Fibers from Lotus Petiole Decorated ZnO Nanoparticles.

Cellulose/ZnO (CZ) nanocomposites are promising antimicrobial materials known for their antibiotic-free nature, biocompatibility, and environmental friendliness. In this study, cellulose fibers extracted from lotus petioles were utilized as a substrate and decorated with various shapes of ZnO nanoparticles (NPs), including small bean, hexagonal ingot-like, long cylindrical, and hexagonal cylinder-shaped NPs. Increasing zinc salt molar concentration resulted in highly crystalline ZnO NPs forming and enhanced interactions between ZnO NPs and -OH groups of cellulose. The thermal stability and UV-visible absorption properties of the CZ samples were influenced by ZnO concentration. Notably, at a ZnO molar ratio of 0.1, the CZ 0.1 sample demonstrated the lowest weight loss, while the optical band gap gradually decreased from 3.0 to 2.45eV from the CZ 0.01 to CZ 1.0 samples. The CZ nanocomposites exhibited remarkable antibacterial activity against both Staphylococcus aureus (S. aureus, Gram-positive) and Escherichia coli (E. coli, Gram-negative) bacteria under visible light conditions, with a minimum inhibitory concentration (MIC) of 0.005mg/mL for both bacterial strains. The bactericidal effects increased with higher concentrations of ZnO NPs, even achieving 100% inhibition. Incorporating ZnO NPs onto cellulose fibers derived from lotus plants presents a promising avenue for developing environmentally friendly materials with broad applications in antibacterial and environmental fields.

A salting-out strategy for the efficient separation of an azeotropic mixture of allyl alcohol and water

Allyl alcohol and water can form the lowest boiling point azeotrope, but it is very hard to acquire high-purity allyl alcohol by normal distillation methods. Herein, a separation and purification protocol is developed for perfectly separating an azeotropic mixture of allyl alcohol and water using the salting-out method, in which three potassium phosphate salts, K5P3O10, K3PO4, and K4P2O7, are systematically investigated as salting-out agents, and finally a product consisting of > 99% allyl alcohol is obtained. A thermodynamic study demonstrates that this process involves endothermy and increment entropy. There is a good correlation between the solubility of allyl alcohol and the molar concentration of salt (mol per 1 kg water), and the solubility of the allyl alcohol in the organic phase or the water phase can be forecast using the mass percentage of salts. This work provides a new methodology for the efficient separation of an azeotropic mixture of allyl alcohol and water.

Tuning polymorphs of precipitated calcium carbonate from discarded eggshells: effects of polyelectrolyte and salt concentration.

Biowaste eggshells are a valuable source of calcium carbonate suitable for various applications. In this study, spherical vaterite and calcite calcium carbonate polymorphs have been synthesised from discarded eggshells by the precipitation technique at ambient temperature. The influence of initial salt concentration with different polyelectrolytes such as ethylene glycol (EG), polyethylene glycol (PEG, 600 and 6000), and poly(sodium 4-styrenesulfonate) (PSS) at various w/v% concentrations on the polymorph crystal formation of precipitated calcium carbonate (PCC) particles was studied. The results indicated that PCC crystals with spherical, star-shaped and yarn shaped morphologies can be obtained based on the concentration of calcium ions and the presence of different polyelectrolyte solution. At low salt molar concentration, PEG-6000 and PSS polyelectrolytes were found to promote the formation of spherical vaterite calcium carbonate particles with particle mean diameters of 5.05 μm and 2.17 μm, respectively. Furthermore, silver nanoparticles were also loaded into the PCC particles in situ, and the surface area significantly increased from 2.2813 m2 g−1 in untreated ground eggshells to 30.4632 m2 g−1 in PCC particles in the presence of PSS and silver colloid solution. The EDS mapping revealed the average wt% of silver atoms loaded in PCC particles in the presence of PSS polyelectrolyte was lower (1.44 wt%) than in the presence of PEG-6000 (4.27 wt%) due to the silver encapsulation possibility during the core–shell formation, as confirmed by SEM images. The silver nanoparticle-loaded PCC particles in this study can be incorporated into the polymer matrix and employed for antimicrobial food packaging or wound dressing application.

Kinetics, absorption and diffusion mechanism of crosslinked Chitosan Hydrogels

Green polymers are extremely useful for various environmental applications. One such biopolymer is Chitosan. In this study, crosslinked and physical Chitosan hydrogels were synthesized. The swelling of disc-shaped hydrogels crosslinked using different concentrations of Glutaraldehyde were compared with physical film and bead shaped hydrogels. Best swelling of around 3000% was observed in case of square film shaped hydrogels but they lacked rigidity and dissolved in mild acids. In case of crosslinked hydrogels, as the crosslinker concentration increased, the hydrogels entrapped less water but gained better mechanical strength. Characterization of synthesized crosslinked hydrogels was carried out using FTIR, TGA and DSC. Equilibrium swelling results indicated more water absorption at acidic pH (2.5). Simultaneously, increase in temperature led to enhancement of swelling degree. The hydrogels trapped more water leading to increased swelling, in case of lower molar salt concentrations. Second order kinetics was followed due to stress relaxation of polymeric chain. Diffusion was found to be anomalous since exponent values lied between 0.5 and 1. Peleg‟s and Exponential association model were used to carry out absorption modeling. The data was found to fit the Peleg‟s absorption model. Degree of swelling is a major factor for deciding a hydrogels utility. Swelling ability, biocompatibility and availability of lone pairs of oxygen and nitrogen on the surface of CS makes it ideal for applications in drug delivery, controlled release of fertilizers and adsorption of environmental contaminants.

High Concentration Electrolytes, or Almost Ionic Liquids, for Advanced Batteries

For most of the commercial life of lithium ion batteries, the electrolyte of choice has been LiPF6 salt in mixtures of organic carbonates, such as ethylene carbonate, propylene carbonate, ethyl carbonate, methyl carbonate and ethyl methyl carbonate1 . In the last several years, however, the electrolyte phase for lithium ion batteries has been given increased scrutiny. One productive area of research has been in the general area of high salt concentration in coordinating organic solvents2. In particular, when the mole ratio of electrolyte salt to coordinating solvent becomes less than 1 to 3 or 4, many changes occur in the solution structure. The amount of free (uncoordinated) solvent drops to undetectable levels, as measured, for example by Raman spectroscopy. This means that the "solvent" is completely coordinated to the cation and the solution now resembles an ionic liquid rather than a mixture of coordinated compact ion pairs and free ions in a medium of the excess free solvent molecules like the conventional 1 molar LiPF6 lithium ion battery electrolyte. The transition to the disappearance of free solvent usually occurs at around 3 to 5 molar salt concentration depending on the salt-solvent combination. It has been known for many years that such transitions occur at high concentrations and models have shown that the degree of association of anion and cation into ion pairs may drop many orders of magnitude3 . Thus, we view such solutions as ionic liquids where a quasi-lattice exists of cations surrounded by anions and anions by cations.Several important effects occur with these solutions. Since the solvent molecules are no longer freely available at the negative electrode interface, the composition of the solid electrolyte interphase (SEI) is found to be quite different from that of the conventional electrolyte. The passivation of the aluminum positive electrode, which in the conventional electrolyte depends upon the unique characteristics of LiPF6 is no longer restricted to the use of this salt. It has been found, for example, that lithium bis-(flurosulfonyl) imide salt - Li(FSO2)2N - in various solvents creates a viable SEI on the negative electrode as well as passivates the Al carrier at the positive electrode. It has also been found that coordinating solvents other than organic carbonates may be used and adequate SEI and Al passivation are observed depending on the salt-solvent combination.There are a couple of negative attributes of these nearly ionic liquid electrolytes, however. The solution viscosity is found to increase dramatically with salt concentration after the disappearance of free solvent. The conductivity is also found to decrease substantially after the transition as well. The use of solvents different from the carbonates, such as small molecule nitriles, gives sufficiently lower viscosity and higher conductivity that these solutions may be of use for lithium ion batteries even at high salt concentration.These aspects will be discussed in detail and some promising results for lithium ion batteries will be presented. In addition, the application of these concepts will be considered for lithium and other metal anode batteries.

Specificity of protein-DNA interactions in hypersaline environment: structural studies on complexes of Halobacterium salinarum oxidative stress-dependent protein hsRosR.

Interactions between proteins and DNA are crucial for all biological systems. Many studies have shown the dependence of protein–DNA interactions on the surrounding salt concentration. How these interactions are maintained in the hypersaline environments that halophiles inhabit remains puzzling. Towards solving this enigma, we identified the DNA motif recognized by the Halobactrium salinarum ROS-dependent transcription factor (hsRosR), determined the structure of several hsRosR–DNA complexes and investigated the DNA-binding process under extreme high-salt conditions. The picture that emerges from this work contributes to our understanding of the principles underlying the interplay between electrostatic interactions and salt-mediated protein–DNA interactions in an ionic environment characterized by molar salt concentrations.

Disordered RNA chaperones can enhance nucleic acid folding via local charge screening

RNA chaperones are proteins that aid in the folding of nucleic acids, but remarkably, many of these proteins are intrinsically disordered. How can these proteins function without a well-defined three-dimensional structure? Here, we address this question by studying the hepatitis C virus core protein, a chaperone that promotes viral genome dimerization. Using single-molecule fluorescence spectroscopy, we find that this positively charged disordered protein facilitates the formation of compact nucleic acid conformations by acting as a flexible macromolecular counterion that locally screens repulsive electrostatic interactions with an efficiency equivalent to molar salt concentrations. The resulting compaction can bias unfolded nucleic acids towards folding, resulting in faster folding kinetics. This potentially widespread mechanism is supported by molecular simulations that rationalize the experimental findings by describing the chaperone as an unstructured polyelectrolyte.

Isolation of intact RNA from murine CD4+ T cells after intracellular cytokine staining and fluorescence-activated cell sorting

Intracellular cytokine staining (ICS) is a powerful method for identifying functionally distinct lymphocyte subsets, and for isolating these by fluorescence activated cell sorting (FACS). Although transcriptomic analysis of cells sorted on the basis of ICS has many potential applications, this is rarely performed because of the difficulty in isolating intact RNA from cells processed using standard fixation and permeabilization buffers for ICS. To address this issue, we compared three buffers shown previously to preserve RNA in nonhematopoietic cells subjected to intracellular staining for their effects on RNA isolated from T lymphocytes processed for ICS. Our results showed that buffers containing the recombinant ribonuclease inhibitor RNasin or high molar concentrations of salt yielded intact RNA from fixed and permeabilized T cells. As proof of principle, we successfully used the buffer containing RNasin to isolate intact RNA from CD4+ T cells that were sorted by FACS on the basis of specific cytokine production, thus demonstrating the potential of this approach for coupling ICS with transcriptomic analysis.

Salting‐out extraction of bio‐based isobutanol from an aqueous solution

AbstractBACKGROUNDMore efficient downstream separation technologies need to be explored due to the low concentration of bio‐based isobutanol in the fermentation broth. The salting‐out extraction of isobutanol from its aqueous solution by employing nine salts (K4P2O7·3H2O, K2HPO4·3H2O, K3PO4·3H2O, K2CO3, K2SO4, KCl, Na2CO3, Na2SO4, NaCl) as salting‐out agents and three organic solvents (2‐ethyl‐1‐hexanol, cyclopentanol, 2‐methyl‐2‐butanol) as extractants were investigated at 298.15 K.RESULTSThe recovery was greatly influenced by the salt concentration and types of salts and organic solvents. When the initial molar K4P2O7 concentration was equal to or higher than 1.01 mol kg‐1 and the mass ratio of aqueous isobutanol solution to 2‐ethyl‐1‐hexanol was 1:1, the recovery of isobutanol reached 100%, and more than 91.62% of water was removed from the organic phase.CONCLUSIONThe salting‐out effects of different anions in nine salts were ordered in the sequence: Cl‐ < SO42‐ < HPO42‐ < CO32‐ < PO43‐ < P2O74‐ at the same initial molar salt concentration and using the same organic solvent. 2‐Ethyl‐1‐hexanol was verified to be the most suitable extractant. The distribution behavior and salting‐out extraction effects can be evaluated by tie‐line correlations and solubility correlation. © 2017 Society of Chemical Industry

ELECTROLYTIC DISSOCIATION OF SODIUM SULFATE IN AQUEOUS ETHANOL SOLUTIONS

The reducing the degree of electrolytic dissociation of sodium sulphate with the increasing a proportion of ethanol in the hydroalcoholic solution was shown with the conductometric method. It was established that the dissociation constant of sodium sulfate decreases with the increasing a concentration of alcohol in the solution. Physico-chemical properties of sodium sulfate in water-alcohol solutions on salt solubility and dissociation were not studied. In this regard, in the present study we examined an electrolytic dissociation of sodium sulfate in water-ethanol solutions. Firstly, a saturated aqueous solution of sodium sulfate, sodium sulfate solubility process was observed with the aid of crystal optic method. For this purpose, a saturated aqueous sodium sulfate was added, and the calculated amount of alcohol measured on mass of precipitated sodium sulfate decahydrate after drying to constant weight. By weight difference between the original and the precipitate salt (calculated as sodium sulphate) dissolved salt mass was measured. It is generally recognized that the degree of dissociation of the electrolyte in the electrolytic solution depends on the dielectric constant of the solvent. Water (e= 78.53) and ethanol (e = 24.3) has vary large permittivity. Therefore, by varying the alcohol content in the mixture with water it may receive different solvents with a dielectric constant, affecting the equilibrium state in the salt solution. To find the degree of electrolytic dissociation used Na2SO4 conductometric method based on measuring the electrical conductivity of solutions with variable molar concentration of salt and alcohol was applied. The dependence of the molar conductivity of aqueous solutions of sodium sulphate is transformed to direct line in coordinate of Kohlrausch equation. It is known that the degree of electrolytic dissociation of the electrolyte depends not only on its nature, but on the dielectric constant of the medium. Therefore, in water-ethanol solutions sodium sulfate shows the properties of weak electrolyte. In this case, the dependence of conductivity on the molar concentration of sodium sulphate in water-ethanol solutions will have a different appearance.Forcitation:Borisov I.M., Nabiev A.A., Mukhamedyanova A.A., Soliev L., Toshov A.F., Musodzhonova Dzh.M. Electrolytic dissociation of sodium sulfate in aqueous ethanol solutions. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 6. P. 59-64.

Direct Analysis of Triterpenes from High-Salt Fermented Cucumbers Using Infrared Matrix-Assisted Laser Desorption Electrospray Ionization (IR-MALDESI).

High-salt samples present a challenge to mass spectrometry (MS) analysis, particularly when electrospray ionization (ESI) is used, requiring extensive sample preparation steps such as desalting, extraction, and purification. In this study, infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) coupled to a Q Exactive Plus mass spectrometer was used to directly analyze 50-μm thick slices of cucumber fermented and stored in 1M sodium chloride brine. From the several hundred unique substances observed, three triterpenoid lipids produced by cucumbers, β-sitosterol, stigmasterol, and lupeol, were putatively identified based on exact mass and selected for structural analysis. The spatial distribution of the lipids were imaged, and the putative assignments were confirmed by tandem mass spectrometry performed directly on the same cucumber, demonstrating the capacity of the technique to deliver confident identifications from highly complex samples in molar concentrations of salt without the need for sample preparation. Graphical Abstract ᅟ.

Structural evidence for solvent-stabilisation by aspartic acid as a mechanism for halophilic protein stability in high salt concentrations.

Halophilic organisms have adapted to survive in high salt environments, where mesophilic organisms would perish. One of the biggest challenges faced by halophilic proteins is the ability to maintain both the structure and function at molar concentrations of salt. A distinct adaptation of halophilic proteins, compared to mesophilic homologues, is the abundance of aspartic acid on the protein surface. Mutagenesis and crystallographic studies of halophilic proteins suggest an important role for solvent interactions with the surface aspartic acid residues. This interaction, between the regions of the acidic protein surface and the solvent, is thought to maintain a hydration layer around the protein at molar salt concentrations thereby allowing halophilic proteins to retain their functional state. Here we present neutron diffraction data of the monomeric zwitterionic form of aspartic acid solutions at physiological pH in 0.25 M and 2.5 M concentration of potassium chloride, to mimic mesophilic and halophilic-like environmental conditions. We have used isotopic substitution in combination with empirical potential structure refinement to extract atomic-scale information from the data. Our study provides structural insights that support the hypothesis that carboxyl groups on acidic residues bind water more tightly under high salt conditions, in support of the residue-ion interaction model of halophilic protein stabilisation. Furthermore our data show that in the presence of high salt the self-association between the zwitterionic form of aspartic acid molecules is reduced, suggesting a possible mechanism through which protein aggregation is prevented.

Activation of biosynthesis of guanyl-specific ribonuclease secreted by Bacillus circulans under salt stress

The gene transcription of guanyl-specific ribonucleases (RNases), which provide available phosphate to cells of Bacillus, is controlled by the signal transduction system PhoP-PhoR. However, the biosynthesis of B. circulans RNase does not depend on the signal-transduction regulatory proteins of Pho regulon. It has been found that raising the salt molar concentration in culture medium increases the level of extracellular guanyl-specific ribonuclease Bci synthesized by B. circulans. Sequences homologous to the binding sites of the regulatory protein DegU were found in RNase Bci promoter. The functioning of the DegS-DegU signal transduction system is stimulated by a high salt concentration. Using a strain of B. subtilis that is defective in the DegU regulatory protein, we have shown that the DegS-DegU system participates in the regulation of RNase Bci expression under salt stress.

Treatment of oil-in-water emulsions by a destabilization/ultrafiltration hybrid process: Statistical analysis of operating parameters

A hybrid process has been studied for an oil-in-water (O/W) emulsion treatment. This process consisted of two stages: emulsion destabilization by coagulation/centrifugation with calcium chloride, and subsequent ultrafiltration (UF) using a 300 kDa tubular multichannel ZrO2 ceramic membrane. The O/W emulsion was formulated from a commercial oil concentrate (1 wt % in distilled water) used in metalworking processes. The hybrid process was optimized in terms of ultrafiltration permeate flux and permeate quality parameters, such as chemical oxygen demand (COD), pH, conductivity and turbidity. Experiments’ planning was designed using Taguchi method to determine the influence of four parameters (transmembrane pressure, feed flow rate to the UF module, destabilization temperature, and coagulant salt molar concentration) on a response factor, with three levels for each of them. The contribution of each factor was determined using a statistical analysis of variance (ANOVA). Transmembrane pressure and temperature were the most significant factors affecting permeate flux, while permeate quality, expressed as COD, was mainly influenced by UF feed flow rate and temperature. This behavior was slightly different when ultrafiltration was performed with 300 kDa flat ZrO2 ceramic membranes.

Kinetic evidence for the effect of salts on the oxygen solubility using laboratory prototype aeration system

This study is dedicated to an accurate evaluation of thermodynamic and kinetic aspects in the oxygenation process of water/salt solutions. Oxygenation has been analyzed by means of kinetic study of oxygen dissolution from the oxygen mass transfer coefficient (KLa) and oxygen transfer rate (SOTR). A stirred, submerged aerated 4-liter system has been designed and the operational conditions have been optimized by studying the influence of hydraulic head, air flow and salinity of water using an optical oxygen sensor. Concerning the thermodynamic phase equilibria, experimental and modeling results are obtained from different binary systems (water/air) and ternary systems (water/air/salts). This information is necessary to predict the composition of the gas phase during the process and is also important for an implementation in a process simulation. The oxygen mass transfer coefficients were firstly measured, by monitoring in the time the oxygen concentration in various synthetic liquid phases containing different salts (NaCl, KCl, LiCl). When compared to clean water, noticeable increase of KLa was observed; the variation of KLa and SOTR with the solution salinity was modeled and found dependent on the nature of cation in the salt added. For all cases, an increase of KLa with increasing salinity was observed but, when the results are correlated with salt molar concentration, very important relation attributed to different salts has been obtained. The present study clearly confirmed the importance to define the experimental conditions before to describe and to model appropriately the gas–liquid mass transfer phenomena.

Comparisons of Tribological Properties of Ti(C,N)/SiC in Water and Seawater

Ti(C,N)-based cermets offer good high temperature strength, perfect chemical stability, excellent wear resistance, and relatively better machinability. In the present work, the tribological behaviors of Ti(C,N)/SiC sliding pairs lubricated in water and seawater were evaluated using a ball-on-disk tribometer. The experimental results show that a relatively low friction coefficient (about 0.025) can be obtained when lubricated with artificial seawater at the sliding speed of 200 mm/s, while the friction coefficient is about 0.2 in purified water. The wear surface profiles and the lubricants collected after running-in process for the high and low friction conditions were compared. In addition, the effects of salt molar concentration of the lubricant on the Ti(C,N)/SiC friction properties were investigated. It was found that the smooth and flat surface is the premise to gain the low friction. At the same time, the proper concentration of silica colloid, which is affected by the salt ions, is also an essential one. Moreover, the high sliding speed (200 mm/s) is beneficial to achieve low friction.

Optimization of a membrane hybrid process for oil-in-water emulsions treatment using Taguchi experimental design

A coagulation–centrifugation/ultrafiltration hybrid process has been performed for the treatment of a commercial oil-in-water emulsion used in metalworking operations. The effect of pre-treatment stage on membrane fouling was evaluated to ascertain the main fouling mechanism and to establish the best membrane cleaning procedure. The hybrid process was optimized in terms of the maximum ultrafiltration (UF) permeate flux. Destabilization temperature, transmembrane pressure, feed flow rate to the UF module, and coagulant salt molar concentration were selected as factors. The experiments were designed using Taguchi method, and the contribution of each factor was determined using a statistical analysis of variance. Experimental results were also discussed in terms of environmental parameters (chemical oxygen demand [COD], conductivity, pH, and turbidity) for the main process streams. The best fit to experimental data of permeate flux decline corresponded to the cake/gel layer formation model. The cleaning procedure combined alkaline and acid washings with mechanical cleaning of membrane surface, and through this combination total permeate flux recovery was achieved. Temperature was the most significant factor affecting permeate flux, followed by coagulant salt concentration, with COD reductions higher than 97.5% for all experimental conditions tested.

Effect of Temperature and Tfsi Concentration on Lithium-Ion Diffusion in (PVDF-HFP)-PYR14 TFSI-LiTFSI Gel Electrolytes

Lithium batteries have been considered as the most probably next generation of power sources for portable electronic devices and electric vehicles. However, safety risks related to the use of highly flammable liquid electrolytes in combination with high voltage electrodes are the main obstacle to their introduction into the market. Recently ionic liquids have emerged as potential materials to substitute the conventional organic carbonate-based liquid electrolytes. In this work we report on the effect of temperature and lithium salt molar concentration on lithium ion diffusion in (PVDF-HFP)-PYR14TFSI-LiTFSI gel electrolytes. TFSI molar ratios range from 0,05 to 1 mol%. The self-diffusion coefficient of lithium ions (D 7Li) was measured at temperatures from 20 to 100°C using the pulsed-field gradient NMR (PFG-NMR) method by using a Bruker 400MHz Avance NMR spectrometer with a magnetic field of 9.4 T. A stimulated echo pulse sequence with gradient pulses of duration (δ) of 1-2 ms and an observation time (Δ) equal to 20 ms was applied. The decay of the signal in dependence on the gradient strength g results in the diffusion coefficient by fitting the exponential decay function. A parallel analysis was made for PYR14TFSI/TFSI ionic liquid electrolytes.The results obtained indicate that the value of D 7Li at high temperature for both liquid and gel electrolytes is practically independent on the LiTFSI molar concentration, while larger differences have been detected at low temperatures, in accordance with ionic conductivity data. The temperature dependence of the calculated self-diffusion coefficients fit the Arrhenius equation. The values of the activation energy Eac, calculated by plotting the shelf diffusion coefficient vs. 1/T, depends on the relative concentration of the lithium salt in the gel, increasing when TFSI molar ratio goes from 0,05 to 1 mol% for both liquid and gel electrolytes.

Chloride and organic osmolytes: a hybrid strategy to cope with elevated salinities by the moderately halophilic, chloride‐dependent bacterium Halobacillus halophilus

Salt acclimation in moderately halophilic bacteria is the result of action of a grand interplay orchestrated by signals perceived from the environment. To elucidate the cellular players involved in sensing and responding to changing salinities we have determined the genome sequence of Halobacillus halophilus, a Gram-positive moderate halophilic bacterium that has a strict requirement for the anion chloride. Halobacillus halophilus synthesizes a multitude of different compatible solutes and switches its osmolyte strategy with the external salinity and growth phase. Based on the emerging genome sequence, the compatible solutes glutamate, glutamine, proline and ectoine have already been experimentally studied. The biosynthetic routes for acetyl ornithine and acetyl lysine are also delineated from the genome sequence. Halobacillus halophilus is nutritionally very versatile and most compatible solutes cannot only be produced but also used as carbon and energy sources. The genome sequence unravelled isogenes for many pathways indicating a fine regulation of metabolism. Halobacillus halophilus is unique in integrating the concept of compatible solutes with the second fundamental principle to cope with salt stress, the accumulation of molar concentrations of salt (Cl(-)) in the cytoplasm. Extremely halophilic bacteria/archaea, which exclusively rely on the salt-in strategy, have a high percentage of acidic proteins compared with non-halophiles with a low percentage. Halobacillus halophilus has an intermediate position which is consistent with its ability to integrate both principles.