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1.
Optimization of culture conditions for the growth rate, 5,8,11,14,17-cis-Eicosapentaenoic acid (EPA) content and EPA productivity of a bacterium isolated from Pacific mackerel intestines was investigated by use of a culture medium containing 1.00 wt% peptone and 0.50 wt% yeast extract in an artificial sea water (ASW). Cultivation temperature affected the growth rate and cellular EPA content of the bacterium. The cellular EPA content at 8°C was as great as 16.8 mg/g of dry cells, which was more than two times greater than that at 25°C (7.3 mg/g of dry cells), although the growth rate showed a maximum at 25°C. Both the yield of bacterial cells and the cellular EPA content at 25°C reached maximum values when the pH of the culture medium was nearly 7.0 and when the concentration of ASW was 100% (v/v). Under optimum culture conditions [25°C pH 7.0 and 100% (v/v) ASW], the amount of EPA accumulated in the cellular lipids reached 45.6 mg/L of culture broth after 8 hr.  相似文献   

2.
The adsorption isotherms of sodium salts of alkyl sulfonic acid and fatty acid with various carbon numbers onto ion exchange resins were measured in the absence and in the presence of sodium chloride in aqueous solutions. In the absence of the inorganic salt, the amount of adsorption remarkably increased with an increase in the length of alkyl groups in the adsorbates. Furthermore, the amount of adsorption apparently decreased with addition of sodium chloride into the solutions and almost reached a constant value at high concentrations of NaCl. This behavior strongly suggested that the electrostatic interaction on the adsorption decreased with increasing salt concentration and that the effect of hydrophobic interaction seems to play an important role on adsorption.  相似文献   

3.
BACKGROUND: The culture medium for optimal growth of vaginal Lactobacillus salivarius CRL 1328 is different from that for optimal bacteriocin production. To simultaneously obtain high amount of biomass and bacteriocin of this microorganism, the effects of different basal culture media and salts on both responses were evaluated. The study was performed by using a complete factorial experimental design 26, with central points. Sixty‐four different growth media, which resulted from the combinations of two basal culture media and two concentrations of five salts (ammonium citrate, sodium acetate, MgSO4, MnSO4, and K2HPO4) were assayed. RESULTS: Only the addition of MnSO4 to each culture medium significantly stimulated the growth of L. salivarius. The presence of sodium acetate or MgSO4 stimulated the bacteriocin production, while MnSO4 and K2HPO4 exerted an inhibitory effect. However, the simultaneous addition of MnSO4 and sodium acetate to both basal culture media allowed high bacteriocin levels to be reached, attenuating the inhibitory effect of Mn2+. CONCLUSIONS: The application of a complete experimental design contributed to simultaneous optimization of the biomass and bacteriocin production of L. salivarius CRL 1328. The results obtained are potentially applicable to the technological production of probiotic bacteria and antagonistic substance to be included in a probiotic pharmaceutical product. Copyright © 2009 Society of Chemical Industry  相似文献   

4.
Tri-n-butyl phosphate (TBP)dissolved in kerosene was chosen as extractant for lithium from a model brine having high magnesium-to-lithium ratio and ferric chloride was added to the system.The influences of contact time,concentration of the extractant,concentrations of some salts (Mg2+,Na+,K+)in the solution,acidity of hydrochloric acid and extraction temperature on the extraction of lithium with TBP-kerosene system were studied.The suitable extraction conditions were found to be :contact time not any less than 20 min;at 20-25℃;[Fe3+]/[Li+]about 1.5-2.0;TBP concentration 50%-70%;[MgCl2]exceeding 3 mol·L-1;pH about 2;while most sodium and potassium salts in the aqueous phase should be removed before the extraction.  相似文献   

5.
Summary A study was made of the degree of splitting of coconut and soybean oils by the Twitchell process at 35±0.1°C. with no shaking or stirring, using an agent consisting mainly of tetrabutyl naphthalene sulfonic acid with water or dilute sulfuric acid. The degree of splitting was greater with sulfuric acid than with water. In general, the degree of splitting of soybean oil was greater when the sulfonic acid was dissolved in the oil layer than when it was in water. The reverse was true with coconut oil. Although addition of glycerol had no effect on the degree of splitting, addition of glacial acetic acid to the coconut oil system decreased fat splitting to a considerable extent. Addition of coconut fatty acids to the coconut oil system had little effect, but soybean fatty acids added to the soybean oil system markedly increased the degree of splitting. For the first time it has been demonstrated that, at 35±0.1°C., splitting of a fat by the Twitchell process occurs in a stepwise way. Coconut oil in contact with 1N sulfuric acid containing the sulfonic acid, corresponding to 1% by the weight of the oil, was about 90% split in 15 to 30 days, depending on the area of contact of the two layers. The diglyceride concentration reached a maximum during the early days of the reaction and then decreased somewhat. Monoglyceride concentration appeared to reach a maximum more slowly and then continued at that level as the concentrations of free fatty acids and glycerol steadily increased. Presented at the symposia on fat of the Chemical Society of Japan, Nov. 10, 1954, and Nov. 8, 1955, Nagoya, Japan; and the 8th annual meeting of the Chemical Society of Japan, Apr. 2, 1955, Tokyo, Japan.  相似文献   

6.
The present work investigates corrosion behaviour of aluminium alloy in 3.5 % sodium chloride medium at 28 °C in the absence and presence of 0.5, 1.0, 1.5 and 2.0 % g/v concentrations of zinc gluconate using gravimetric and electrochemical techniques. The aluminium alloy was cut to corrosion coupons, and immersed into 3.5 % sodium chloride solution containing different inhibitor concentrations (0.5, 1.0, 1.5 and 2.0 % g/v) within a period of twenty-eight days. The surface morphology of the metal was examined by high resolution scanning electron microscopy equipped with energy dispersive spectroscopy (HR-SEM/EDS). From the results, it was found that the adsorption of zinc gluconate reduced aluminium alloy corrosion in the sodium chloride medium. Experimental results also showed that inhibition efficiency increased with an increase in zinc gluconate concentration. Furthermore, potentiodynamic polarization results revealed decrease in corrosion rates (CR), corrosion current densities (Icorr), and increasing corrosion resistance (Rp) in the presence of zinc gluconate in 3.5 % NaCl solution. Tafel polarization analyses indicated that zinc gluconate is a mixed type inhibitor. The adsorption of zinc gluconate on the aluminium alloy surface followed Langmuir adsorption isotherm.  相似文献   

7.
Lipids of the marine oomycetous microbe Haliphthoros philippinensis were characterized by chromatographic and spectroscopic techniques. Total lipid content of this organism was relatively low and not very responsive to manipulation of the culture conditions. Neutral lipid comprised 21% of the total lipid and the polar lipids were mainly phosphatidylcholine (44%), phosphatidylethanolamine (15%), and a ceramide-phosphorylethanolamine (19%). Palmitic (16:0) was the primary saturated fatty acid at 25% of the total fatty acids, and arachidonic acid (20:4n-6, ARA) and eicosapentaenoic acid (20:5n-3, EPA) were the major unsaturated fatty acids at 19 and 21%, respectively. Fucosterol was the principal sterol at 59% of the total sterols. The effects of several cultivation variables on growth and EPA production by this species were investigated. Among those tested, glucose and sodium glutamate were the most efficient carbon and nitrogen sources for growth, respectively. When the mycelium was cultivated for 6 d to produce biomass under optimal growth conditions, and then transferred to low temperature for an additional 13 d without glucose, the EPA content reached 31% of the total fatty acids and the yield was 203 mg/L. When the same experiment was performed with glucose supplementation during the low-temperature phase, EPA composed 27% of total fatty acids and yield reached 316 mg/L, or a 285% increase over that from mycelium cultured for 6 d at 24°C, and 56% over that cultured at 16°C for 13 d. ARA production did not respond accordingly.  相似文献   

8.
无机盐对三甘醇脱水及发泡性能影响研究   总被引:1,自引:0,他引:1  
孟江  李永树  张燕  陈玥利 《广东化工》2012,39(14):22-24
在天然气净化工艺过程中,三甘醇会受到天然气所携带高矿化度地层水的污染,影响生产。因此,通过实验分析了氯化钠、碳酸氢钠、氯化钙以及氯化铁等无机盐对三甘醇富液脱水和发泡、消泡的影响。研究结果表明,三甘醇富液含水量越大,脱水需要的时间越长,且不易脱除;三甘醇富液脱水率随氯化钠、氯化钙和碳酸氢钠浓度的增大而下降。钙离子对三甘醇富液脱水影响要大于钠离子,碳酸根离子的影响大于氯离子;对于发泡来说,氯化钙影响最小,但氯化钠、氯化钙和碳酸氢钠都存在一个引起三甘醇富液(含有十二烷基磺酸钠)发泡高度最大的浓度,碳酸氢钠的最大,氯化钙的最小;消泡方面,三种盐存在一个消泡最大时间对应的浓度范围,这个浓度范围氯化钙最小,碳酸氢钠最大。氯化铁浓度增大使三甘醇富液脱水率缓慢下降,在研究范围内,总体变化不大;三甘醇富液发泡高度及消泡时间随氯化铁加入浓度的增大而增大,在氯化铁浓度达到0.12%(重量浓度)趋于平缓。  相似文献   

9.
The effect of three dissolved salts namely sodium chloride, calcium chloride and zinc chloride on the heat of mixing (endothermic) of the binary system 2-propanol-benzene has been experimentally investigated. The salts were dissolved in the component in which they were preferentially soluble to concentrations up to 15% by weight wherever possible. The experimentation was done at 30°C using a standard type calorimeter attached to a micro-processor based control unit M1PROC The established experimental procedure was followed. The salts sodium chloride and zinc chloride brought about an enhancement in the heat of mixing values. Calcium chloride on the other hand has been found to produce an opposite effect.  相似文献   

10.
Khari salt and NaCl are traditional preservatives for raw hides/skin used for leather processing. With well known efficiencies and low cost of curing these sodium salts are applied widely in India. These curing salts generate a huge amount of pollution and salinity in the form of total dissolved solids (TDS) and chlorides (Cl) during leather processing. Therefore various investigating groups have been involved in formulating alternative curing systems. With this view, an attempt has been made to evolve a least chloride containing curing system for salinity abatement. In our research work we had introduced an attempt towards salinity treatment in the Kanpur region with another sodium salt i.e. sodium sulphate. In this study we have now compared sodium sulphate salts with NaCl and Khari salts for various paradigms of analysis including moisture content, deterioration rate, bacteriostatic properties and SEM. Results proved that sodium sulphate salts are several folds better than conventional salts cured stock. Since sodium sulphate salts reduce the chloride content from the effluent and also effectively reduce TDS and TSS in the final effluent, they are ideally suited for hide preservation.  相似文献   

11.
Concrete cylinders, 255 mm in diameter, were made with high- and low-alkali cements, a highly alkali-silica-reactive coarse aggregate, and subjected to various conditions at 38 °C: (1) immersion in 3% NaCl solution; (2) immersion in 6% NaCl solution; (3) humid air at 100% RH, and (4) 14-day cycles including 12 days in humid air, 2 days of drying, and 3 h in 6% NaCl solution. After 1 year, a number of cylinders were drilled to obtain dry powder samples from different depths, which were analyzed for total and soluble chloride and for soluble sodium and potassium. Concrete cores were also taken in a number of parapets and abutments, either exposed to deicing salts or not, on which chemical analyses were also performed on slices taken at different depths from the exposed surface. The results obtained suggest that making concrete with a low-alkali content is an effective way to prevent expansion due to alkali-silica reaction even for concretes exposed to seawater or deicing salts; this is attributed to the fact that the OH ion concentration in the pore solution, and then the pH, is decreased in the near-surface layers of concrete exposed to sodium chloride, which does not penetrate at depth in concrete.  相似文献   

12.
The decomposition temperature and pressure (quadruple point) of chlorodifluoromethane (R22) gas hydrate in aqueous sodium chloride (NaCl) solution was measured at different NaCl concentrations in the solution as a phase diagram. The operative concentration curve of NaCl was obtained as a function of temperature. The maximum decomposition temperature of R22 hydrate was about 290 K at 0.9 MPa pressure, and it decreased as the NaCl concentration increased in the solution. R22 hydrate caused supercooling, and the supercooling occurrence temperature was much lower than the decomposition temperature. The ultrasonic charge reduced the supercooling of hydration effectively even though the ultrasonic charge did not change the decomposition temperature at all. The concentration experimental results from the several NaCl solutions having different NaCl concentrations were in good agreement with the theoretical operative concentration curve for NaCl.  相似文献   

13.
Dilute solution viscosity of a series of random copolymers of acrylamide (AM) with sodium-2-acrylamido-2-methylpropane sulfonate (NaAMPS) and with sodium-2-sulfoethylmethacrylate (NaSEM) has been studied using a four-bulb shear dilution capillary viscometer. The hydrodynamic volume of the copolymers in aqueous media was determined as a function of salt concentration, temperature, shear rate, and time. A linear relationship was observed between the intrinsic viscosity [η]0 and the reciprocal of the square root of ionic strength in sodium chloride solutions, with salt concentrations varying from 0.043M to 0.257M. Negative temperature coefficients for [η]0 indicate a decrease in the hydrodynamic volume of the ionic polymer molecules with increasing temperature. The relative zero-shear-intrinsic-viscosity change in distilled water to 0.257M sodium chloride aqueous media is used to elucidate viscosity–structure relationships. A maximum value is reached for this parameter at a composition of about 30 mol % of ionic comonomers for AM–NaAMPS and AM–NaSEM copolymer series.  相似文献   

14.
The effect of sodium benzoate and sodium chloride on the aggregation behavior of PEO-PPO-ph-PPO-PEO (BPE) and PPO-PEO-ph-PEO-PPO (BEP) polyethers at the air/water interface was investigated by measuring the equilibrium surface tension, surface dilational viscoelasticity, and surface tension relaxation. The measurements of surface tension showed that sodium benzoate has a better effect on decreasing the surface tension of BPE and BEP solutions than NaCl, especially when the polyether concentrations are low. According to dilational viscoelasticity measurements, the concentration of BPE required for the maximum dilational modulus is lower than that of BEP, indicating that BPE more easily forms a compact adsorbed layer. The dilational modulus values of BPE solutions in the presence of sodium benzoate and NaCl first increase and then decrease after passing through a maximum, and then they increase again with increasing electrolyte concentration. On the other hand, the dilational modulus values of BEP solutions in the presence of sodium benzoate and NaCl first increase to a maximum and then decrease with increasing electrolyte concentration. The surface tension relaxation results are consistent with those of dilational viscoelasticity. The different effects of sodium benzoate and NaCl on the polyether aggregation behaviors are caused by the strong hydrophobic and π-π interactions between polyethers and sodium benzoate. This work has a great importance for the application and development of polyethers.  相似文献   

15.
新型氯化钠浮选药剂的研制   总被引:1,自引:0,他引:1  
采用自行开发的氯化钠浮选剂对旱要光卤石进行选别试验,闭路试验表明,精矿含KCl23.7%,NaCl4.13%,尾矿含KCl2.90%,NaCl84.03%,精矿KCl回收率可达96.79%,NaCl排除率达84.70%。  相似文献   

16.
苯甲醛反应沉淀分离L-精氨酸   总被引:2,自引:0,他引:2  
考察了pH值、苯甲醛与L-精氨酸的摩尔比、氯化钠和氯化铵浓度、L-赖氨酸与L-精氨酸的质量比及L-精氨酸初始浓度等因素对苯甲醛反应沉淀L-精氨酸的影响. 结果表明,苯甲醛反应沉淀L-精氨酸的pH>11为宜;苯甲醛与L-精氨酸的摩尔比为1.25时,L-精氨酸的沉淀率可达到90%以上;氯化钠对沉淀基本上没有影响,而氯化铵浓度增大则沉淀率迅速下降;当L-赖氨酸与L-精氨酸的质量比小于1时L-精氨酸沉淀率仍可以在80%以上,当它们的质量比大于1以后,沉淀率迅速下降;L-精氨酸初始浓度应在15 g/L以上才可保证沉淀在90%以上.  相似文献   

17.
BACKGROUND: Polysaccharides isolated from medicinal mushrooms have been shown to exhibit antitumour bioactivity, but the quality and quantity of these polysaccharides are affected by variations in medium composition and operational conditions in the submerged culture. This study was conducted to elucidate quantitatively the effects of sodium chloride (NaCl) supplementation on the production and quality of exopolysaccharides from the medicinal mushroom Phellinus linteus. RESULTS: Supplementation of NaCl to submerged cultures of P. linteus significantly affected the morphology, the exopolysaccharide (PLPS) production, its average molecular weight and its biological activity. Phellinus linteus grew in a filamentous form in NaCl‐free medium, but a pellet form became predominant as NaCl supplemention increased. The specific growth rate decreased monotonically from 0.18 to 0.01 day?1 as the NaCl concentration increased from 0.0 to 2.0 g dm?3 (34.22 mmol dm?3); however, the specific product yield increased monotonically from 3.9 to 98.4 mg g?1 (25.2‐fold enhancement). Both 14.3‐fold enhancement (from 23 to 329 mg dm?3) in the production of PLPS and 1.5‐fold enhancement (from 670 to 995 pg TNF‐α (tumour necrosis factor α) cm?3) in its biological activity were achieved as the NaCl concentration increased from 0.0 to 1.0 g dm?3 (17.11 mmol dm?3). The biological activity of PLPS was highly correlated with its average molecular weight (coefficient R2 = 0.90). CONCLUSION: The average molecular weight of PLPS was key to its biological activity. Both the quantity and bioactivity of PLPS could be significantly enhanced by appropriate NaCl supplementation to the submerged culture of the medicinal mushroom. Copyright © 2008 Society of Chemical Industry  相似文献   

18.
In this paper the influence of ammonium salt concentration on the production of pharmaceutical grade plasmid DNA from unfed high cell density batch culture on synthetic glycerol media is presented. Ammonium chloride in different concentrations (0 mmol dm?3, 18.7 mmol dm?3, 37 mmol dm?3 and 74 mmol dm?3 supplemented) was used beside sodium glutamate as nitrogen source. Plasmid DNA concentrations of more than 50 mg dm?3 were obtained with 37 mmol dm?3 ammonium. The homogeneity of the DNA produced was confirmed by agarose and capillary gel electrophoresis and found to fulfil the quality requirements set for biopharmaceutical plasmid DNA with more than 90% in the supercoiled form. Copyright © 2003 Society of Chemical Industry  相似文献   

19.
在酸性环境中通过NaCl电解协同NaClO2化学氧化方法制备的复合二氧化氯溶液中ClO2和自由氯浓度分别达到70%和20%左右,系统地研究了电流密度(A)、NaClO2与NaCl质量比(B)、电解时间(C)对复合溶液中组分浓度和质量百分数的影响,并将复合溶液用于城市污水二级处理出水的消毒。结果表明,复合溶液中自由氯的浓度主要受因素C和A的影响,ClO2的浓度主要受因素C和B的影响,而A对副产物ClO2-和ClO3-的影响最大。总大肠菌群数在105~108个.L-1的城市污水二级处理出水采用复合溶液消毒时,当其中ClO2投加量为4 mg/.L-1,自由氯含量不低于1.20mg.L-1,经30min接触后出水生物学指标满足GB/ T18920-2002 的要求。既降低了消毒剂的使用量,又减少了消毒副产物ClO2-的生成。  相似文献   

20.
NaCl在聚电解质溶液中活度系数的实验测定   总被引:6,自引:0,他引:6       下载免费PDF全文
引 言聚电解质是指在极性溶剂中能够电离形成聚离子和反离子的高分子[1] ,在生物体中广泛存在 ,如蛋白质、DNA和RNA等都是聚电解质 ,聚丙烯酸盐和聚苯乙烯磺酸盐则是典型的人工合成聚电解质 .在聚电解质的水溶液中 ,由于聚离子带有大量的电荷 ,对反离子具有很强的静电吸引作用 ,即使在极低的浓度下溶液仍具有很大的非理想性 ,这与普通电解质溶液显著不同[2 ,3 ] .建立聚电解质溶液热力学性质的计算方法一直是溶液理论研究的热点 ,现已取得长足进展 ,如Manning的反离子凝聚理论[2 ,3 ] 、柱状胞腔模型基础上的PB方程理论[4 ,…  相似文献   

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