Varying Salt Concentrations Research Articles

Salinity Acclimation Strategies in Nitrifying Bioreactors

Several industries, including aquaculture, produce effluents with high or varying salt concentrations. The treatment of such effluents by the biological nitrification process can be challenging, as the microbes performing this process are sensitive to salinity. In certain cases, such as in recirculating aquaculture systems (RAS), it is essential to maintain high nitrification efficiency during salinity changes to prevent ammonia and nitrite toxicity. Therefore, suitable strategies are required to make nitrifying bioreactors tolerant to salinity variations. Although salinity changes can impact the nitrification performance, it has been shown that nitrifying bioreactors can acclimate to salinity variations over several days. This acclimation can be due to the physiological adaptation of the existing microorganisms or due to selection for microorganisms adapted to that salinity regime. Other factors, such as the biofilm matrix, can also play a role in salinity acclimation. Recent studies have shown that microbial management strategies can be applied to improve the salinity tolerance and reduce the recovery time of nitrifying bioreactors. Here, we discuss the existing knowledge on salinity acclimation in nitrifying systems, and recent advances in strategies to make nitrifying biofilms more tolerant to salinity variations. We also propose directions for future research to improve our understanding of the salinity acclimation mechanisms in nitrifying systems.

Effect of salinity and surfactant on volatile fatty acids production from kitchen wastewater fermentation

Effects of the various concentrations of salt (0.5–12 g/L NaCl), surfactants (0.005–0.12 g/L LAS), and their co-presence on fermentative volatile fatty acids (VFAs) production from kitchen wastewater were investigated. VFAs production declined by 17–84% with increasing salt concentration from 3 to 12 g/L, whereas it was enhanced by 10–25% at surfactant concentrations of 0.03–0.12 g/L. The addition of 0.06 g/L surfactants in kitchen wastewater marginally improved VFAs production in different salt amended (0.5–12 g/L) reactors. Acetate and propionate were the major VFAs under all conditions; however, the percentage of propionate increased by 15–22% with increasing surfactant concentration. Higher alpha diversity indices values of the bacterial population were noted in the reactors amended with surfactant. Enterobacteriales were the dominant order of bacteria present in the reactor amended with 6 g/L of salt, whereas Lactobacillales were most prominent in reactor amended with 0.06 g/L of surfactant.

Electric Potential of Citrate-Capped Gold Nanoparticles Is Affected by Poly(allylamine hydrochloride) and Salt Concentration.

The structure near polyelectrolyte-coated gold nanoparticles (AuNPs) is of significant interest because of the increased use of AuNPs in technological applications and the possibility that the acquisition of polyelectrolytes can lead to novel chemistry in downstream environments. We use all-atom molecular dynamics (MD) simulations to reveal the electric potential around citrate-capped gold nanoparticles (cit-AuNPs) and poly(allylamine hydrochloride) (PAH)-wrapped cit-AuNP (PAH-AuNP). We focus on the effects of the overall ionic strength and the shape of the electric potential. The ionic number distributions for both cit-AuNP and PAH-AuNP are calculated using MD simulations at varying salt concentrations (0, 0.001, 0.005, 0.01, 0.05, 0.1, and 0.2 M NaCl). The net charge distribution (Z(r)) around the nanoparticle is determined from the ionic number distribution observed in the simulations and allows for the calculation of the electric potential (ϕ(r)). We find that the magnitude of ϕ(r) decreases with increasing salt concentration and upon wrapping by PAH. Using a hydrodynamic radius (RH) estimated from the literature and fits to the Debye-Hü̈ckel expression, we found and report the ζ potential for both cit-AuNP and PAH-AuNP at varying salt concentrations. For example, at 0.001 M NaCl, MD simulations suggest that ζ = -25.5 mV for cit-AuNP. Upon wrapping of cit-AuNP by one PAH chain, the resulting PAH-AuNP exhibits a reduced ζ potential (ζ = -8.6 mV). We also compare our MD simulation results for ϕ(r) to the classic Poisson-Boltzmann equation (PBE) approximation and the well-known Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. We find agreement with the limiting regimes─with respect to surface charge, salt concentration and particle size─in which the assumptions of the PBE and DLVO theory are known to be satisfied.

Effect of pre-treatment and oil popping conditions on quinoa popping quality

Abstract Quinoa is a pseudocereal having outstanding nutritional profile and health-promoting biofunctional compounds. It is able to pop into an affordable, crispy, and flavourful ready-to-eat snack by conventional oil-popping method. Oil-popping is the process of frying grains in hot oil for a short time to induce vapour-driven expansion of grains. The effects of process variables on oil-popping quality of quinoa were evaluated. The conditions of processing were optimised using Response Surface Methodology. The grains (10 g) were hydrated by adding 0.1–0.3 mL of water containing a varying salt concentration of 0–1%, w/w and popped in coconut oil maintained at a popping temperature of 200–240 °C for a popping time of 10–30 s. The developed popped quinoa was analysed for popping quality indices. It was found that the increase in popping temperature, popping time, and salt concentration, and decrease in moisture level significantly decreased bulk density but increased popping yield (% popped grains), expansion ratio (degree of volume expansion), and flake size (average kernel size) of popped quinoa. Overall acceptability of popped quinoa in terms of sensory attributes was positively correlated with popping temperature and popping time. The optimised variables generated a popping yield of 75.56%, expansion ratio of 3.07, flake size of 11.58 mm3, bulk density of 0.29 g mL−1, and overall acceptability score of 8.40. A threefold expansion and a fair popping yield obtained from oil-popped quinoa offer a significant potential to generate profit for manufacturers.

Salt Tolerant Indigenous Zn Solubilizing Bacteria Isolated from Forest Organic Soils Promotes Yield and Root Growth in Oryza Sativa under Zinc Deficient Alluvial Soil

The present study conducted to identifying and characterizing the efficient Zn solubilizing rhizobacteria isolated from chickpea and peas rhizosphere owing distinct plant growth advancing qualities for zinc-inadequate alluvial soil. Out of ten, Four strains ZnJ11, (Klebsiella pneumonia- MT509804), ZnJ10 (Acinetobacter calcoaceticus- MT509803), ZnJ15A (Acinetobacter pittii- MT509805), and ZnJ2A (Pantoea agglomerans- MT509806) were selected using basal medium contained insoluble Zn minerals such as ZnO and ZnPO4 at concentrations of 2000 µg/mL. In qualitative assay, ZnJ11 showed maximum zinc solubilization efficiency (SE: 525 ± 2.9 and pH-7.5), followed by ZnJ10 showed (SE: 383 ± 3.1 and 329 ± 3.2, pH-7.5) in all three Zn sources, then ZnJ15A and ZnJ2A exhibited (SE: 306 ± 2.2 and 206 ± 1.7) respectively. Contrary to plate assay, zinc solubilization in liquid medium quantified by AAS also revealed efficacy of all the strains. Bacterial growth and Zn solubilization at variable salt concentration (0–10%) and pH (4.5–10) was measured that showed Klebsiella sp. tolerate (8% & 6.5–8.5), Acinetobacter calcoaceticus (6% & 6.5–10), Acinetobacter pittii (10% & 6.5–10) and Pantoea sp. (8% & 5.5–10) respectively. In addition, all strains were showed different degree of susceptibility to tested antibiotics at variable concentrations. Simultaneously, phytostimulating properties like IAA production, nitrogen fixation, phosphate solubilization, potassium solubilization, siderophore production, ammonia production, HCN and amylase, cellulose, pectinase and catalase were also tested. Bio-inoculation of A. calcoaceticus × P. agglomerans was done in rice crop (HUR 105) with different combination of zinc oxide and zinc sulfate in pot experiment. Findings revealed that root growth (31 ± 1.6), straw yield (32.4 ± 1.7), and grain yield (13 ± 2.0) in the treatment of ZnO (Zn-8.0 kg/ha) with Bio-inoculation was found superior over all treatments. The positive action of Bio-inoculation was also exhibited on growth and yield parameters.

Effect of Potassium Alum Salt Particles on the Activation Energy of Poly(ethylene oxide) Doped with Conductive Carbon Black (CB) Nanoparticles

The electrical properties of conductive carbon black (CB) nanoparticles (0.1wt percent) doped thin films made of poly(ethylene oxide) (PEO) filled with varying amounts of the electrolyte potassium alum salt and doped with conductive carbon black (CB) nanoparticles (0.1wt percent) have been investigated. The dependence of the activation energy of the composites on frequency, temperature, and filler content was studied using the AC impedance technique. The current research looked at how activation energy changed with frequency (200-1000 kHz) and temperature (30-55oC) for composites with varied potassium alum salt concentrations: 0, 2, 4, 8, 12, and 16 wt. percent. The activation energy (Ea) values measured exhibited frequency, temperature, and filler content relationships. According to polarization processes, the activation energy of the produced sheets decreases with the potassium alum salt content in the composite and decreases with the temperature. With increasing frequency, the activation energy of the produced thin films decreases.

Coupling Mixed Mode Chromatography/ESI Negative MS Detection with Message-Passing Neural Network Modeling for Enhanced Metabolome Coverage and Structural Identification.

A key unmet need in metabolomics continues to be the specific, selective, accurate detection of traditionally difficult to retain molecules including simple sugars, sugar phosphates, carboxylic acids, and related amino acids. Designed to retain the metabolites of central carbon metabolism, this Mixed Mode (MM) chromatography applies varied pH, salt concentration and organic content to a positively charged quaternary amine polyvinyl alcohol stationary phase. This MM method is capable of separating glucose from fructose, and four hexose monophosphates a single chromatographic run. Coupled to a QExactive Orbitrap Mass Spectrometer with negative ESI, linearity, LLOD, %CV, and mass accuracy were assessed using 33 metabolite standards. The standards were linear on average >3 orders of magnitude (R2 > 0.98 for 30/33) with LLOD < 1 pmole (26/33), median CV of 12% over two weeks, and median mass accuracy of 0.49 ppm. To assess the breadth of metabolome coverage and better define the structural elements dictating elution, we injected 607 unique metabolites and determined that 398 are well retained. We then split the dataset of 398 documented RTs into training and test sets and trained a message-passing neural network (MPNN) to predict RT from a featurized heavy atom connectivity graph. Unlike traditional QSAR methods that utilize hand-crafted descriptors or pre-defined structural keys, the MPNN aggregates atomic features across the molecular graph and learns to identify molecular subgraphs that are correlated with variations in RTs. For sugars, sugar phosphates, carboxylic acids, and isomers, the model achieves a predictive RT error of <2 min on 91%, 50%, 77%, and 72% of held-out compounds from these subsets, with overall root mean square errors of 0.11, 0.34, 0.18, and 0.53 min, respectively. The model was then applied to rank order metabolite IDs for molecular features altered by GLS2 knockout in mouse primary hepatocytes.

Novel solid biopolymer electrolyte based on methyl cellulose with enhanced ion transport properties

AbstractMagnesium ion conducting solid polymer electrolyte films are prepared with biodegradable methyl cellulose and Mg(NO3)2.6H2O by solution casting method. FTIR spectrum of the films confirmed the interaction between the polymer host and the metal salt. FTIR deconvolution gives a clear picture of the percentage of free ions with the salt concentration variation. Structural modification of the polymer upon salt doping are studied with XRD analysis. Glass transition temperature of the pristine film is found to increase with the concentration of the salt, which is attributed to an increase in the coordination between Mg+2 and oxygen atoms of the polymer matrix and formation of transient crosslinks. TGA analysis accounts for the thermal stability of the electrolyte films. The electrical properties of the films have been analyzed, and the values of ionic conductivities of the films were calculated. Electrolyte film with 25 wt% of the salt, which is highly amorphous, is found to have the highest room‐temperature ionic conductivity of 1.02 × 10−4 S cm−1. SEM micrographs show variation in the surface morphology of the electrolytes with the variation in the concentration of the salt. The films' electrochemical stability window and ionic transference number are calculated to find the suitability for energy storage applications.

A capacitor-based power equivalent model for salinity-gradient osmotic energy conversion

Converting the salinity-gradient into electricity via ion migration in nanoconfined channels driven by the salt concentration gap between sea and river water is an important renewable energy utilization method. The osmotic energy conversion device is regarded as a power source with constant voltage output in the conventional constant voltage source (V-source) power equivalent circuit model, which is based on a steady state with constant concentration on both sides of the membrane. In this study, an unsteady equivalent capacitor–capacitor/resistor (C-CR) power equivalent circuit model is proposed to consider the salt concentration variation during actual operation. The maximum relative deviation of the calculated short circuit current between the C-CR power equivalent circuit model and the measured experimental data is 7.06%. The maximum relative deviation of the predicted maximum output power density between the C-CR power equivalent circuit model and the measured experimental data is less than 14.22%, while the corresponding maximum deviation for the V-source power equivalent circuit model has an error of 38.14%. A parallel encapsulation method by embedding graphene oxide membranes (GOMs) into polydimethylsiloxane (PDMS) is provided to offer an extended accessible area for ion transport to enhance the ion flux and output power density. This method reveals a linearly increased output power with the number of GOMs, which provides convenience for increasing output power. This work provides an effective way to design integrated osmotic energy conversion devices, which promotes the development of salinity-gradient-driven energy conversion systems.

Chemical and Antioxidant Activity Changes in Philippine Green Mussel (Perna viridis) during Fermentation at Varying Salt Concentrations

Green mussel (Perna viridis) is an extensively cultured bivalve species in the Philippines and a cheap source of valuable nutrients such as essential amino acids and minerals. Experimental samples were prepared by mixing salt to varying mussel meat ratios (1:3, 1:5, 1:7, and 1:9) which were assessed for changes in pH, degree of hydrolysis, and antioxidant activities during fermentation for 30 d. The pH levels in treatments 1:3, 1:5, and 1:7 decreased to low-acid levels (&lt; pH 4.6) as fermentation progressed. Meanwhile, treatment 1:9 did not significantly change from its initial pH level with a slight decrease noted during 15 d but significantly increased at slightly neutral pH level (at 7.22) on 30 d. Formaldehyde nitrogen (formol-N) and the simultaneous formation of ammonia-N significantly increased (p &lt; 0.05) with prolonged fermentation time but were more pronounced in 1:7 and 1:9 treatments. The gradual increase in pH and formol-N in treatments 1:3 and 1:5 could be due to the high salt content at 23.63 ± 0.29 %, and 19.48 ± 0.88 %, respectively, which could have slowed down proteolytic enzyme activity. However, continuous increase in ammonia-N in treatment 1:9 significantly reduced (p &lt; 0.05) amino-N content which lowers the nutritional quality of fermented products. The development of antioxidant activities such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, ferric reducing antioxidant power (FRAP), and total phenol content (TPC) as gallic acid equivalent (GAE) was highest in treatments 1:7 and 1:9. These findings could be attributed to the increasing degree of protein breakdown producing substances and reaction products with increased bioactivity. This is also supported by the significant positive linear correlation between formol-N and antioxidant system assays (DPPH, FRAP, and TPC) (p &lt; 0.01)

Protective role of exogenously supplied salicylic acid and PGPB (Stenotrophomonas sp.) on spinach and soybean cultivars grown under salt stress

Managing sustainable crop production under escalating soil salinity will be a great challenge in coming years. Exogenous application of protectants has been recognized to ameliorate the adverse effects of salinity through better growth performance of plant. Present study was conducted to assess the potential role of salicylic acid (SA) and PGPB (Stenotrophomonas sp.) on spinach and soybean cultivars grown under the two variable salt concentrations. The result of the study showed that the 100 ppm salt caused more severe effects than 50 ppm salt on both selected crops and their cultivars. Salt stress induced H2O2 generation and MDA accumulation, developed ionic imbalance, increased electrolyte leakage, and decreased biomass and yield. However, exogenous supply of protectants improves plant growth and yield, enhanced RWC, accumulated osmolytes, and increased enzymatic and non-enzymatic antioxidants with both the level of salinity. Moreover, applied protectants induced new protein bands and disappearance of some other expressed protein with different molecular weight provides a purpose for bearing more salt under salt stress conditions. Study concluded that the exogenously supplied PGPB and SA manage salinity-induced yield loss through increased growth, osmotic adjustment, protein accumulation, and APX activity. However, ionic balance does not have major role in protectant induced salinity tolerance. Study also finds PGPB more effective protectant than SA for reducing the salinity induced yield loss due to strong low molecular weight protein profiling, higher strength of ionic homeostasis and higher APX activity.

Conditions for High Rate, High Capacity Li-Ion Convection Cells through Dimensional Analysis

Improved performance of Li-ion cells for applications, such as, electric vehicles, renewable energy storage, and grid load leveling, calls for both high energy and rate capability. An implied high capacity under high rate cell (dis)charge is presently very difficult or unachievable in closed Li-ion cells. A common limitation under such demands is electrolyte transport and frequently Li-ion salt bulk diffusion in particular. The limitation leads to salt concentration variation and depletion in the cathode. A convection cell with in-operation electrolyte flow can significantly mitigate this limitation under quantitatively defined ranges of conditions, as published recently.1 This finding emerged from the addition of convection to a DUALFOIL-based pseudo 2D Li-ion cell model to create LIONSIMBA+c and dimensional analysis of input electrolyte transport properties, dimensions, and operational parameters. With cell performance output expressed as %capacity accessed, inputs combined into dimensionless groups explain the balance of migration versus diffusion and convection and allow for collapse of myriad output data points into families of curves for analysis.Here, we elaborate on the LIONSIMBA+c result analysis including the dimensionless groups that describe Li-ion cell capacity limitations with and without flow. Full material working capacity is achievable with low current or fast electrolyte transport – diffusion or convection. Notably, flow serves as an operational throttle for obtaining desirable transport. With discharge rate increase or sluggish transport, deliverable capacity drops precipitously and asymptotically approaches reduced levels, particularly when there is low initial Li-ion salt amount. A material balance explains the reduced capacity values at high rate. The accessible discharge time and thus capacity is gated by the time that migration depletes Li-ion salt in the cathode. We also examine the corresponding common electrolyte concentration profile behavior under different parameter combinations with similar dimensionless group values. Reference Gao, M. J. Orella, T. J. Carney, Y Román-Leshkov, J. Drake, and F. R. Brushett, J. Electrochem. Soc. 167 140551 (2020).

A Study On The Influence Of Sodium Salt Solution On The Atterberg Limits And Swelling Of Bentonite Clay

Due to industrialization and subsequent rise in urbanisation, our groundwater system and geoenvironmental reserves are getting degraded due to detrimental effects of industrial wastes discarded off into the geo-environment. Basic components like water, air and soil all get degraded resulting unacceptable loss of their natural virtues like purity, renewability, stability, sustainability and tolerability. Major industrial effluents like salt solutions, chemicals, artificial dyes, heavy metals, pharmaceutical residues and sewages etc., are posing the major problems for the ecosystem and their subparts. Since, bentonite clay has peculiar characteristics of high swelling and high pollutant absorbing capacity along with low hydraulic conductivity, it is used as a geotechnical clay liner. However, the geotechnical parameters of bentonite get affected on interaction with cations present in salt solutions. This investigation was carried out in order to observe the influences of salt solutions on bentonite and the results obtained depicts that the varying salt concentrations have a definite influence on Atterberg limits, swelling of bentonite.

Effect of varying salt concentration on iridescence in precooked pork meat

The objective of this study was to investigate the effect of salt concentration on meat iridescence in cured cooked pork products. In addition, the influence of nitrite and pigmentary color on iridescence and its visual macroscopic perception was ascertained. Sample cubes from the pigs M. longissimus thoracis et lumborum were salted with either NaCl (20 g/kg, 40 g/kg) or nitrite curing salt (6 g/kg, 20 g/kg, and 40 g/kg) and subsequently cooked. Control samples were not salted. The effects of NaCl and curing salt on iridescence, instrumental color and microstructure were evaluated. Salt treatment significantly (p < 0.05) increased water-holding capacity, mean myofibers diameters and iridescence and reduced light scattering (L* value). An iridescence limit was reached with the 20 g/kg salt treatments. No differences between sodium chloride and nitrite curing salt were observed for both visual evaluation and colorimetry of the interference colors. Iridescence increases were attributed to a swelling of the myofilament lattice and thus reduction of intermyofibrillar spaces as well as an optical clearing of the myofibrils by dissolution of myofibrillar proteins that both reduce light scattering and allow more reflectance and interference to occur.Graphic abstract

Controlling supraparticle shape and structure by tuning colloidal interactions

HypothesisAssembly of colloids in drying colloidal suspensions on superhydrophobic surface is influenced by the colloidal interactions, which determine the shape and interior structure of the assembled supraparticle. The introduction of salt (electrolyte) into the assembly system is expected to influence the colloid interactions and packing during the evaporation process. Hence, both the outer shape and internal structure of supraparticles should be controlled by varying salt concentrations. ExperimentsSuspensions of electrostatically stabilized polystyrene particles with specified salt concentrations were chosen as model systems to conduct the evaporation on a superhydrophobic surface. A systematic study was performed by regulating the concentration and valency of salt. The morphology and interior of supraparticles were carefully characterized with electron scanning microscopy, while the colloidal interaction was established using colloidal probe atomic force microscopy. FindingsSupraparticles displayed a spherical-to-nonspherical shape change due to the addition of salts. The extent of crystallization depended on salt concentration. These changes in shape and structure were correlated with salt-dependent single colloid interaction forces, which were not previously investigated in detail in radially symmetric evaporation geometry. Our findings are crucial for understanding assembly behavior during the drying process and offer guidance for preparing complex supraparticles to meet specific applications requirement.

Siderite Dissolution in Mars-analog Brines: Kinetics and Reaction Products

Abstract This study examines siderite (FeCO3) reactivity in MgCl2 and MgSO4 brines with varying salt concentrations (0.01M, 1M, and 3M) at both acidic (pH ∼ 2 and pH ≤ 2) and near-neutral (pH ∼ 7) conditions. We measured aqueous Fe concentrations through time to determine dissolution rates and characterized the solid reaction products with scanning electron microscopy, electron dispersive X-ray spectroscopy, and Raman spectroscopy. Iron-based siderite dissolution rates at pH 2 were equivalent in the 0.01M and 1M MgSO4 brines and slower in 3M MgSO4; rates in the MgCl2 brines slow systematically with increasing brine concentration for equivalent initial pH values. Fe-based dissolution rates could not be determined in the neutral pH experiments due to precipitation of iron (hydr)oxide phases. After 1 day in acidic brines, abundant etch pits were observed; however, in the neutral experiments, siderite was identified with Raman spectroscopy even after 1 yr of dissolution along with a range of iron (hydr)oxide phases. Scanning electron microscopy imaging of the neutral experiment products found Mg-sulfate brines produced a chaotic surface texture. Therefore, micron-scale textural observations could be used to discriminate between alteration in chloride and sulfate brines. Initial iron release rates were similar in dilute brines, but decreased by less than an order of magnitude in the two highest-concentration pH 2 brine experiments; therefore, siderite-bearing assemblages exposed to acidic fluids, regardless of salinity, would likely dissolve completely over geologically short periods of time, thus erasing siderite and likely other carbonate minerals from the geologic record.

Salt-Dependent Conformational Changes of Intrinsically Disordered Proteins.

The flexible structure of an intrinsically disordered protein (IDP) is known to be perturbed by salt concentrations, which can be understood by electrostatic screening on charged amino acids. However, an IDP usually contains more uncharged residues that are influenced by the salting-out effect. Here we have parametrized the salting-out effect into a coarse-grained model using a set of Förster resonance energy transfer data and verified with experimental salt-dependent liquid-liquid phase separation (LLPS) of 17 proteins. The new model can correctly capture the behavior of 6 more sequences, resulting in a total of 13 when varying salt concentrations. Together with a survey of more than 500 IDP sequences, we conclude that the salting-out effect, which was considered to be secondary to electrostatic screening, is important for IDP sequences with moderately charged residues at physiological salt concentrations. The presented scheme is generally applicable to other computational models for capturing salt-dependent IDP conformations.

Isolation and characterization of salt-tolerant bacteria with plant growth-promoting activities from saline agricultural fields of Haryana, India

BackgroundSoil salinity has been one of the biggest hurdles in achieving better crop yield and quality. Plant growth-promoting rhizobacteria (PGPR) are the symbiotic heterogeneous bacteria that play an important role in the recycling of plant nutrients through phytostimulation and phytoremediation. In this study, bacterial isolates were isolated from salt-polluted soil of Jhajjar and Panipat districts of Haryana, India. The potential salt-tolerant bacteria were screened for their PGPR activities such as phosphate solubilization, hydrogen cyanide (HCN), indole acetic acid (IAA) and ammonia production. The molecular characterization of potent isolates with salt tolerance and PGPR activity was done by 16S rDNA sequencing. ResultsEighteen soil samples from saline soils of Haryana state were screened for salt-tolerant bacteria. The bacterial isolates were analyzed for salt tolerance ranging from 2 to 10%. Thirteen isolates were found salt tolerant at varied salt concentrations. Isolates HB6P2 and HB6J2 showed maximum tolerance to salts at 10% followed by HB4A1, HB4N3 and HB8P1. All the salt-tolerant bacterial isolates showed HCN production with maximum production by HB6J2. Phosphate solubilization was demonstrated by three isolates viz., HB4N3, HB6P2 and HB6J2. IAA production was maximum in HB4A1 (15.89) and HB6P2 (14.01) and least in HB4N3 (8.91). Ammonia production was maximum in HB6P2 (12.3) and least in HB8P1 (6.2). Three isolates HB6J2, HB8P1 and HB4N3 with significant salt tolerance, and PGPR ability were identified through sequencing of amplified 16SrRNA gene and were found to be Bacillus paramycoides, Bacillus amyloliquefaciens and Bacillus pumilus, respectively. ConclusionsThe salt-tolerant plant growth-promoting rhizobacteria (PGPR) isolated from saline soil can be used to overcome the detrimental effects of salt stress on plants, with beneficial effects of physiological functions of plants such as growth and yield, and overcome disease resistance. Therefore, application of microbial inoculants to alleviate stresses and enhance yield in plants could be a low cost and environmental friendly option for the management of saline soil for better crop productivity.

Hydrophobic mullite ceramic hollow fibre membrane (Hy-MHFM) for seawater desalination via direct contact membrane distillation (DCMD)

A low-cost hydrophobic mullite hollow fibre membrane (Hy-MHFM) fabricated via phase inversion/sintering technique followed by fluoroalkyl silane (FAS) grafting is presented in this study. The prepared CHFMs were characterized before and after the grafting step using different characterization techniques. The pore size of the CHFM surface was also determined using ImageJ software. The desalination performance of the grafted membrane was evaluated in direct contact membrane distillation (DCMD) using synthetic seawater of varying salt concentrations for 2 h at various feedwater temperatures. The outcome of the evaluations showed declines in the permeate flux of the membrane at increasing feed concentration, as well as increased flux with increased feed temperature. The long-term stability of the membrane was achieved at time 20 h, feed temperature 60 °C, and permeate temperature 10 °C, the membrane achieved a salt rejection performance of about 99.99 % and a water flux value of 22.51 kg/ m2 h.

Salt, glucose, glycine, and sucrose protect Escherichia coli O157:H7 against acid treatment in laboratory media

This study investigated the effects of combinations of acetic or malic acid and various solutes (salt, glucose, glycine, or sucrose) on the survival of Escherichia coli O157:H7 in laboratory broth. Additionally, the effectiveness of combining organic acids and various concentrations of salt (0–18%) or sucrose (0–100%) with different water activity values against E. coli O157:H7 were evaluated. For treatment of 1% malic acid, the addition of 3% salt showed synergistic effect. Whereas, when 3% salt, glucose, glycine, or sucrose was added to 1% acetic acid, the solutes antagonized the action of the acid against E. coli O157:H7. Acetic, lactic, or propionic acid combined with salt at either 7 or 9% or sucrose at 60, 80, or 100% resulted in the highest resistance of E. coli O157:H7. From a result of evaluating the membrane fatty acid (MFA) composition of cells, salt or sucrose significantly increased levels of saturated fatty acids (SFAs) or SFAs and cyclopropane fatty acids, respectively. From the results of this study, the addition of solutes and organic compounds may increase the tolerance of E. coli O157:H7 to acetic, lactic, and propionic acid treatments and that the salt or sucrose significantly affects cell MFA composition.