Wide Range Of NaCl Concentrations Research Articles

Isolation and Identification of<i> Halomonas</i> sp. ZSCW-10: A Moderately Halophilic Bacteria Strain with Cellulase Activity

A moderately halophilic bacteria strain with cellulase (CMCase) activity, ZSCW-10, which can survive under wide range of NaCl concentration (1 %~15 %, w/v) and pH (4.5~9.0), was isolated from the sediment of intertidal zone located in the Xiangshan Island, Zhejiang Province. The strain was identified based on 16S rDNA sequence determination and phylogenetic analysis together with its morphological and physiological characterization. The results indicated that the 16S rDNA homologies were 97% between strain ZSCW-10 and some strains of Halomonas sp.. The phylogenetic tree was constructed with Molecular Evolutionary Genetics Analysis version 5 (MEGA5), showed the closest relationship between strain ZSCW-10 and Halomonas venusta. Based on its physiological and biochemical properties, homology and phylogenetic analysis, strain ZSCW-10 was identified as a subspecies of Halomonas sp.. The optimum culture conditions were: NaCl 6.0%, 32°C, pH 7.5.

Effect of ionic strength and molecular weight on electrical properties and thickness of polyelectrolyte bi-layers

Electric light scattering from aqueous suspensions of positively charged ferric oxide particles is investigated in the presence of poly(sodium styrene sulfonate) and poly(allylamine hydrochloride) of different molecular weights, adsorbed sequentially on the particle surface at different ionic strengths. The adsorption is realized over a wide range of NaCl concentration (10−4 to 10−1M) at pH 4.5 and the suspensions of coated particles are then rinsed to ionic strength of 10−4M. Our measurements indicate that the amplitude of the electro-optical effect increases with increasing concentration of NaCl from 10−4 to 10−2M due to the increased amount of polymers, adsorbing in more coiled conformation and on more highly charged particle surface. However, the electro-optical effect started to decrease at further increase of NaCl concentration, more expressively at higher field intensities and for bi-layers with first layer from polyelectrolyte of lower molecular weight. This is accompanied with a significant increase in the thickness of the deposited bi-layers after their rinsing to low ionic strength. We attribute both effects to partial desorption of polyelectrolyte complexes from the particle surface, which disturb the homogeneity of the bi-layer structure. The latter causes an increase in the amount of mechanically trapped water on the particle surface and the thickness of adsorbed bi-layers increases as well. As a result, an elasto-hydrodynamic effect, which favors perpendicular orientation with respect to the external electric field, becomes possible.

Galvanically Induced Intergranular Corrosion of AA5083-H131 Under Atmospheric Exposure Conditions: Part 1—Experimental Characterization

In a two-part series of papers, the galvanic corrosion behavior of sensitized aluminum alloy (AA)5083-H131 (UNS A95083) when coupled with AISI 4340 (UNS G43400) steel was studied experimentally and computationally, with an emphasis on atmospheric conditions. In Part 1, the electrochemical kinetics of AA5083-H131 and steel in salt solutions of relevance to atmospheric corrosion were determined, including the influence of the degree of sensitization (DoS), potential, and sodium chloride (NaCl) concentration in the context of intergranular corrosion (IGC) propagation. More severe IGC was seen on materials with higher degrees of DoS, with damage depths of 1 mm or more developing in 100 h. The extent of IGC damage over 100 h was proportional to potential for a wide range of NaCl concentrations. These results from full immersion were compared with exposure testing and scanning Kelvin probe (SKP) measurements conducted under atmospheric conditions. It was found that the extent and spatial distribution of IGC damage on the atmospherically exposed material corresponded well to the IGC damage distribution expected from the SKP potential measurements and the damage results from the full immersion experiments. These findings are used as the input data for the computational model to predict the IGC damage distribution presented in the second paper.

Autoprotolysis in water/methanol/NaCl ternary systems

A potentiometric method was used to determine the autoprotolysis constant for aqueous solutions containing 0, 20 and 40 mass % of methanol over a wide range of NaCl concentrations at 25 °C. The ionic strength ranged between 0.25 and 2.00 mol L -1 at intervals of 0.25 units. The osmotic and activity coefficients of the mixed solvents were calculated as a function of ionic strength. The dependence on ionic strength was analyzed using the ori.- ginal specific ion interaction theory. The specific ion interaction parameters associated with the thermodynamic autoprotolysis constant were extracted. Results indicate that interaction between ions increases with increasing metha- nol content in the mixture.

Utilization of renewable agricultural residues for the production of extracellular halostable cellulase from newly isolated Halomonas sp. strain PS47

A newly isolated biopolymer-degrading halophilic bacterium, Halomonas sp. strain PS47, yielded higher cellulase activity (0.0076 U/ml) in mineral salt medium (MM63). Activity increased to 0.029 U/ml when carboxymethyl cellulose (0.5 % w/v) was used as carbon source and further to 0.138 U/ml when a combination of yeast extract and peptone was used as nitrogen source. Enzyme secretion was maximal during late exponential and stationary phases (0.15 U/ml, 48 h). Among different agro-residues (1 % w/v), wheat bran gave the highest activity (0.12 U/ml) at pH 7.5, 30 °C and 6 % (w/v) NaCl. The cellulase exhibited higher activity at pH 7.1 and 50 °C. The enzyme exhibited activity over a wide range of NaCl concentrations (0–4 M). Optimum activity was at 0–1 M NaCl. At 4 M NaCl, activity was reduced to 65 % of the initial value. The present investigation thus contributes to the limited information available on halostable cellulases.

Purification and biochemical characterization of a cold-active lipase from Antarctic sea ice bacteria Pseudoalteromonas sp. NJ 70

An extracellular cold-active lipase from Antarctic sea ice bacteria Pseudoalteromonas sp. NJ 70 was purified and characterized. The overall purification based on lipase activity was 27.5-fold with a yield of 25.4 %. The purified lipase showed as a single band on SDS-PAGE with an apparent molecular weight of 37 kDa. The optimum temperature and pH were 35 °C and 7.0, respectively. The lipase activity was enhanced by Ca(2+) and Mg(2+), while was partially inhibited by other metals such as Cu(2+), Zn(2+), Ba(2+), Pb(2+), Fe(2+) and Mn(2+). The lipase had high tolerance to a wide range of NaCl concentrations (0-2 M NaCl). It exhibited high levels of activity in the presence of DTT, Thiourea, H(2)O(2) as well as in the presence of various detergents such as Span 60, Tween-80, Triton X-100. In addition, the lipase showed a preference for long-chain p-nitrophenyl esters (C(12)-C(18)). These results indicated that this lipase could be a novel cold-active lipase.

Crystal Growth of Clathrate Hydrate at the Interface between Seawater and Hydrophobic-Guest Liquid: Effect of Elevated Salt Concentration

This paper reports the visual observations of the clathrate hydrate crystal growth and morphology at the interface of aqueous NaCl solutions and a guest-substance liquid. The hydrate crystal growth was visually characterized in the systems of a wide range of NaCl concentrations from 0.035 to 0.264 in mass fraction. The mass fraction 0.035 was corresponding to that of ordinary seawater, and the salt concentration tested was extended up to the saturation level, i.e., 0.264. Cyclopentane was used as the guest substance. Formation and growth of hydrate crystals at the cyclopentane-NaCl solution interface were observed. We visually analyzed the individual hydrate crystals and classified the morphology of the crystals according to ΔTsub at atmospheric pressure. It was found that the size of the individual hydrate crystals decreased with increasing ΔTsub. The results showed that the morphology of the individual hydrate crystals in any NaCl concentration is roughly similar at a given ΔTsub. We also measured the l...

Dewetting of Silica Surfaces upon Reactions with Supercritical CO2 and Brine: Pore-Scale Studies in Micromodels

Wettability of reservoir minerals and rocks is a critical factor controlling CO(2) mobility, residual trapping, and safe-storage in geologic carbon sequestration, and currently is the factor imparting the greatest uncertainty in predicting capillary behavior in porous media. Very little information on wettability in supercritical CO(2) (scCO(2))-mineral-brine systems is available. We studied pore-scale wettability and wettability alteration in scCO(2)-silica-brine systems using engineered micromodels (transparent pore networks), at 8.5 MPa and 45 °C, over a wide range of NaCl concentrations up to 5.0 M. Dewetting of silica surfaces upon reactions with scCO(2) was observed through water film thinning, water droplet formation, and contact angle increases within single pores. The brine contact angles increased from initial values near 0° up to 80° with larger increases under higher ionic strength conditions. Given the abundance of silica surfaces in reservoirs and caprocks, these results indicate that CO(2) induced dewetting may have important consequences on CO(2) sequestration including reducing capillary entry pressure, and altering quantities of CO(2) residual trapping, relative permeability, and caprock integrity.

Influence of electrolyte and poloxamer 188 on the aggregation kinetics of solid lipid nanoparticles (SLNs)

Solid lipid nanoparticles (SLNs) have attracted increasing attention as colloidal drug carriers due to theirs advantages including low toxicity, drug targeting and modified release. However, undesired particle aggregation in aqueous dispersions would limit the applicability of SLNs for drug delivery. The purpose of the present article is to investigate the aggregation behavior of the SLNs and quantitatively evaluate how the concentration of NaCl and F68 affect the stability of the SLNs. The early stage aggregation kinetics of the SLNs was investigated over a wide range of NaCl concentrations by employing dynamic light scattering (DLS). In the presence of the NaCl, aggregation kinetics of the SLNs exhibited reaction-limited (slow) and diffusion-limited (fast) regimes. These results indicated that the aggregation behavior of these new nanoparticles can be well explained by the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The critical coagulation concentration (CCC) of SLNs containing 0.0%, 0.1%, 0.5%, 2.0%, and 4.0% of Poloxamer 188 (F68) was 416, 328, 519, 607, and 602 mM, respectively, suggesting that the F68 influences the aggregation behavior of the SLNs. F68 made the SLNs more sensitive to the electrolyte when its concentration is low (0.1%), the bush of the polymer F68 has a bridging effect that accelerated the aggregation process of the SLNs. However, at the high concentration, F68 can provide the steric repulsion to the nanoparticles, which effectively stabilized the SLNs dispersions.

Biodegradation of polycyclic aromatic hydrocarbons by a halophilic microbial consortium

In this study we investigated the phenanthrene degradation by a halophilic consortium obtained from a saline soil sample. This consortium, named Qphe, could efficiently utilize phenanthrene in a wide range of NaCl concentrations, from 1% to 17% (w/v). Since none of the purified isolates could degrade phenanthrene, serial dilutions were performed and resulted in a simple polycyclic aromatic hydrocarbon (PAH)-degrading culture named Qphe-SubIV which was shown to contain one culturable Halomonas strain and one unculturable strain belonging to the genus Marinobacter. Qphe-SubIV was shown to grow on phenanthrene at salinities as high as 15% NaCl (w/v) and similarly to Qphe, at the optimal NaCl concentration of 5% (w/v), could degrade more than 90% of the amended phenanthrene in 6days. The comparison of the substrate range of the two consortiums showed that the simplified culture had lost the ability to degrade chrysene but still could grow on other polyaromatic substrates utilized by Qphe. Metabolite analysis by HPLC and GC-MS showed that 2-hydroxy 1-naphthoic acid and 2-naphthol were among the major metabolites accumulated in the Qphe-SubIV culture media, indicating that an initial dioxygenation step might proceed at C1 and C2 positions. By investigating the growth ability on various substrates along with the detection of catechol dioxygenase gene, it was postulated that the uncultured Marinobacter strain had the central role in phenanthrene degradation and the Halomonas strain played an auxiliary role in the culture by utilizing phenanthrene metabolites whose accumulation in the media could be toxic.

A Novel Halophilic Lipase, LipBL, Showing High Efficiency in the Production of Eicosapentaenoic Acid (EPA)

BackgroundAmong extremophiles, halophiles are defined as microorganisms adapted to live and thrive in diverse extreme saline environments. These extremophilic microorganisms constitute the source of a number of hydrolases with great biotechnological applications. The interest to use extremozymes from halophiles in industrial applications is their resistance to organic solvents and extreme temperatures. Marinobacter lipolyticus SM19 is a moderately halophilic bacterium, isolated previously from a saline habitat in South Spain, showing lipolytic activity.Methods and FindingsA lipolytic enzyme from the halophilic bacterium Marinobacter lipolyticus SM19 was isolated. This enzyme, designated LipBL, was expressed in Escherichia coli. LipBL is a protein of 404 amino acids with a molecular mass of 45.3 kDa and high identity to class C β-lactamases. LipBL was purified and biochemically characterized. The temperature for its maximal activity was 80°C and the pH optimum determined at 25°C was 7.0, showing optimal activity without sodium chloride, while maintaining 20% activity in a wide range of NaCl concentrations. This enzyme exhibited high activity against short-medium length acyl chain substrates, although it also hydrolyzes olive oil and fish oil. The fish oil hydrolysis using LipBL results in an enrichment of free eicosapentaenoic acid (EPA), but not docosahexaenoic acid (DHA), relative to its levels present in fish oil. For improving the stability and to be used in industrial processes LipBL was immobilized in different supports. The immobilized derivatives CNBr-activated Sepharose were highly selective towards the release of EPA versus DHA. The enzyme is also active towards different chiral and prochiral esters. Exposure of LipBL to buffer-solvent mixtures showed that the enzyme had remarkable activity and stability in all organic solvents tested.ConclusionsIn this study we isolated, purified, biochemically characterized and immobilized a lipolytic enzyme from a halophilic bacterium M. lipolyticus, which constitutes an enzyme with excellent properties to be used in the food industry, in the enrichment in omega-3 PUFAs.

High temperature positively modulates oxidative protection in salt-stressed cashew plants

This work evaluated the oxidative protection mechanisms triggered by high temperatures in salt-stressed cashew ( Anacardium occidentale) plants. In the first experiment, cashew plants in a greenhouse were subjected to a wide range of NaCl concentrations under natural conditions involving high temperatures. In the second experiment, the plants were exposed to 100 mM NaCl alone, heat alone (42 °C) or a combination of both heat and NaCl. Data analysis from the two experiments revealed that salt-stressed plants were favored by high temperatures in terms of oxidative protection, as indicated by a decrease in lipid peroxidation and H 2O 2 concentration. The H 2O 2 concentration and lipid peroxidation results were corroborated in long-term salt exposure in a greenhouse; however, greenhouse plants that were subjected to high salinity exhibited mild protein oxidation. High temperature positively modulated protein content and the activities of catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) in salt-stressed plants, but salinity exerted a negative effect on APX activity. The changes in ascorbate redox state were favorable for cashew protection under high salinity combined with heat. The data demonstrate that high temperature is essential for the oxidative protection of salt-stressed cashew plants, which display an efficient protection mechanism represented by the activities of CAT, SOD and APX as well as favorable changes in the ascorbate redox state under acute salt stress.

Improved measurements of Na + fluxes in plants using calixarene-based microelectrodes

Ion-selective microelectrodes are a powerful tool in studying adaptive responses of plant cells and tissues to various abiotic stresses. However, application of this technique in Na + flux measurements was limited due to poor selectivity for Na + ions of commercially available Na + cocktails. Often, these cocktails cannot discriminate between Na + and other interfering ions such as K + and Ca 2+, leading to inaccurate measurements of Na + concentration and, consequently, inaccurate Na + flux calculations. To overcome this problem, three Na +-selective cocktail mixtures were prepared using tetramethoxyethyl ester derivative of p-t-butyl calix[4]arene. These cocktail mixtures were compared with commercially available ETH 227-based Na + cocktail for selectivity for Na + ions over other ions (particularly K + and Ca 2+). Among the three calixarene-based Na + cocktails tested, cocktail 2 [in % w/w: Na + ionophore (4- tert-butylcalix[4]arene-tetra acetic acid tetraethyl ester) 3.5, the plasticizer (2-nitrophenyl octyl ether) 95.9 and lipophilic anion (potassium tetrakis (4-chlorophenyl) borate) 0.6] showed the best selectivity for Na + ions over K + and Ca 2+ ions and was highly stable over time (up to 10 h). Na + flux measurements under a wide range of NaCl concentrations (25–150 mM) using Na + cocktail 2 established a clear dose–response relationship between severity of salt stress and magnitude of Na + influx at the distal elongation and mature zones of Arabidopsis thaliana roots. Furthermore, Na + cocktail 2 was compared with commercially available ETH 227-based Na + cocktail by measuring Na + fluxes at the two Arabidopsis root zones in response to 100 mM NaCl treatment. With calixarene-based Na + cocktail 2, a large decreasing Na + influx (0–15 min) followed by small Na + influx (15–45 min) was measured, whereas with ETH-based Na + cocktail Na + influx was short-lived (1–3 min) and was followed by Na + efflux (3–45 min) that might have been due to K + and Ca 2+ efflux measured together with Na + influx. In conclusion, Na +-selective calixarene-based microelectrodes have excellent potential to be used in real-time Na + flux measurements in plants.

A halotolerant Alcanivorax sp. strain with potential application in saline soil remediation

Biodegradation of petroleum compounds in saline environments seems intricate and needs more attention. In this study, tetracosane was used to enrich alkane-degrading bacteria from oil-contaminated saline soils. Among the isolates, strain Qtet3, with the highest 16s rRNA gene sequence similarity to Alcanivorax dieselolei B-5(T), was able to grow at a wide range of NaCl concentrations and was shown by GC analysis to degrade more than 90% of tetracosane in 10 days. This strain has at least two alkB genes and could grow on crude oil and diesel fuel, and utilize various pure aliphatic hydrocarbon substrates (from C(12) to C(34)). Highly hydrophobic cell surfaces and lack of significant surface tension reduction in the media suggest that the main mechanism of the cells for accessing substrate is to attach directly to hydrocarbon particles. Application of this strain for remediating crude oil-contaminated soils irrigated with defined saline water demonstrated that this halotolerant bacterium could survive and grow in saline soils irrigated with NaCl solutions up to 5% w/v, with the highest hydrocarbon degradation of 26.1% observed at 2.5% NaCl. This strain is promising for future industrial applications especially in bioremediation of saline soils and wastes.

Characterization and stability studies on surfactant, detergent and oxidant stable α-amylase from marine haloalkaliphilic Saccharopolyspora sp. A9

A halopalkaliphilic marine Saccharopolyspora sp. stain A9 with an ability to produce surfactants, oxidant and detergent stable α-amylase was isolated from marine sediments collected from west coast of India. The α-amylase from strain A9 was purified to homogeneity with the aid of ammonium sulfate precipitation and gel filtration chromatography by using Sephadex G-75, insoluble corn starch and sephacryl S-100 column, with a 39.01-fold increase in specific activity. SDS-PAGE and zymogram activity staining showed a single band equal to molecular mass of 66 kDa. Enzyme was found to be stable in presence of wide range of NaCl concentration with maximum activity found at 11% (w/v) of NaCl. Enzyme showed remarkable stability towards laboratory surfactants, detergents and oxidants. Glucose, maltose and maltotriose were the main end product of starch hydrolysis, indicating it is α-amylase.

Germination variation in Arabidopsis thaliana accessions under moderate osmotic and salt stresses

Water and salt stresses are two important environmental factors that limit the germination of seeds in most ecological environments. Most studies conducted so far to address the genetic basis of the above phenomenon have used stress conditions that are much more extreme than those found in natural environments. Furthermore, although an excess of ions and water restrictions have similar osmotic effects on germination, the common and divergent signalling components mediating the effects of both factors remain unknown. The germination of seeds was compared under solutions of NaCl (50 mm) and polyethylene glycol (PEG, -0·6 MPa), that establish mild stress conditions, in 28 Arabidopsis thaliana accessions. Because Bayreuth (Bay) and Shadara (Sha) accessions showed contrasting sensitivity responses to both stresses, a quantitative trait locus (QTL) analysis was carried out using Bay × Sha recombinant inbred lines (RILs) to identify loci involved in the control of germination under mild salt and osmotic stresses. Two loci associated with the salt sensitivity response, named SSR1 and SSR2 QTLs, and four loci for the osmotic sensitivity response, named OSR1-OSR4 QTLs, were mapped. The effects of the SSR1 QTL on toxic salt sensitivity, and the osmotic contribution of OSR1, were confirmed by heterogeneous inbred families (HIFs). Whilst the SSR1 QTL had a significant effect under a wide range of NaCl concentrations, the OSR1 QTL was confirmed only under moderate drought stress. Interestingly the OSR1 QTL also showed pleiotropic effects on biomass accumulation in response to water deficit. The regulation of germination under moderate salt and osmotic stresses involves the action of independent major loci, revealing the existence of loci specifically associated with the toxic component of salt and not just its osmotic effect. Furthermore, this work demonstrates that novel loci control germination under osmotic stress conditions simulating more realistic ecological environments as found by populations of seeds in nature.

The Use of Chloro-Complexation to Enhance Cadmium Uptake by Zea mays and Brassica juncea: Testing a “Free Ion Activity Model” and Implications For Phytoremediation

Maize and Indian mustard plants were studied to: 1) investigate the effect of Cl− complexation on Cd uptake from soil historically amended with sewage sludge (Cd 58 mg kg−1) and, 2) model the uptake of Cd by these plants with a Free Ion Activity Model (FIAM). Plants were treated with NaCl (50 to 300 mM in the soil pore water) along with controls using Na2SO4. Cadmium enhanced solubility in soil by Cl− generally reflected increases in Cd uptake by both plants. The free ion Cd2+ activity in soil solution, as modeled by WHAM-VI, remained almost unchanged despite the wide range of NaCl concentrations. Therefore, Na+ exchange for Cd2+ could not fully explain the differences in Cd content between the Cl− treatments because of the high buffering Cd2+ capacity in soil. Activities of Cd-chloro complexes showed the best correlations with the Cd concentrations in the plants compared to the activity of Cd2+. The FIAM showed a reasonable good fit for the plants when assuming competition by Cd2+ and CdCl+ for root sorption sites. Indirect evidence suggests that CaSO4 precipitation may have limited the formation of CdSO4 complexes and reduced Cd soil solubility. The implications of these results for phytoremediation are discussed.

Isolation of Photobacterium sp. LuB-1 and its application in rapid assays for chemical toxicants in water

To isolate marine bacteria with strong bioluminescence in a wide range of NaCl concentration, especially at low salt conditions. A luminous bacterium named LuB-1 was isolated from China. It was identified by biochemical analysis and phylogenetic analysis based on the 16S rRNA gene and designated as Photobacterium sp. The isolate is capable of emitting strong and stable luminescence in a wide range of NaCl concentration from 0.2 to 5% (w/v). For most toxic agents tested in this study, the response of LuB-1 was better than that of MicrotoxVibrio fischeri under both low salt (0.9% NaCl) and high salt (2.0% NaCl) conditions. The strain LuB-1 had an obvious predominance of bioluminescence in a wide range of NaCl concentration and better response for heavy metal pollutants and some organic toxicants in both low and high salt toxicity test systems. Because of its good sensitivity in a wide range of salt concentration, the strain LuB-1 should have its unique advantage in rapid assay for toxicants in water with different salt concentrations.

Gene expression and characterization of a novel GH family 18 chitinase from extremely halophilic archaeon Halobacterium salinarum NRC-1

An open reading frame encoding a chitinase homolog (ChiN1) was found in the genome of extremely halophilic archaeon Halobacterium salinarum NRC-1. ChiN1 is a multidomain enzyme consisting of a chitin-binding domain, a polycystic kidney disease domain and a catalytic domain belonging to glycoside hydrolase family 18. chiN1 gene was successfully expressed in extremely halophilic archaeon Haloarcula japonica TR-1 by employing the promoter sequence of its cell surface glycoprotein gene. A large amount of recombinant ChiN1 was secreted into the culture supernatant. The Ha. japonica-produced ChiN1 was purified and characterized. The optimal pH and temperature of ChiN1 are pH 4.5 and 55°C, respectively. ChiN1 was most active at 1.0 M NaCl and stable over a wide range of NaCl concentration from 1.0 to 4.5 M. This is the first report on a chitinase from extremely halophilic archaeon.

Effects of Salinity Changes on the Growth of Dunaliella salina and Its Isozyme Activities of Glycerol-3-phosphate Dehydrogenase

Dunaliella salina could survive in media containing a wide range of NaCl concentrations ranging from about 0.05 M to saturation (around 5.5 M). Glycerol is an important osmolyte when Dunaliella survive in various salt environments, and G3pdh is a key enzyme in glycerol metabolism. The osmotic response of D. salina was investigated by studying its cell growth, glycerol content change, and isozyme activity of glycerol-3-phosphate dehydrogenase (G3pdh) in different salinities. Results showed that 2.0 M NaCl was the optimal salinity for the growth of D. salina, in which condition the highest glycerol content of 64.02 +/- 3.21 (mean +/- SD) microg/mL was detected. D. salina could rapidly increase or decrease glycerol contents to adapt to hypoosmotic or hyperosmotic environments. The glycerol content declined 52.05% when salinity was changed from 2.0 to 0.5 M NaCl, and the glycerol content increased 43.61% when salinity was increased from 2.0 to 5.0 M NaCl. In the isozyme electrophoresis assay two kinds of isozymes, G3pdh and superoxide dismutase (Sod), were detected synchronously. Interestingly, it was first found that there are five isozymes of G3pdh in D. salina. G3pdh-2 mainly takes effect in moderate to high salinities, whereas the other four isozymes take effect in low salinities, which may provide an important clue for future research on osmoregulation mechanisms.