, one of the typical representatives of chiral materials, having been attracted more and more attention for the controllable and adjustable advantages such as composition, structure, morphology, permittivity parameter, permeability parameter and chiral parameters.Regular helical nanofibers are prepared by the chemical vapor deposition of acetylene with copper nanocrystals as a catalyst at the low temperature of 250℃. The copper nanocatalyst used in this study is obtained from the thermal decomposition of copper tartrate precursor. The morphologies of the fibers could be simply controlled by adjusting reaction temperature, calefaction speed, and the acetylene flow rate. could be known by TEM and SEM analysis that these helical nanofibers grown over single copper nanocrystal exhibited a mirror-symmetric growth mode: the two helical nanofibers had identical coil diameter, coil pitch, cycle number, and fiber diameter, but had absolutely opposite helical senses. The morphologies of the fibers could be changed in the processes of fibers growth, and the shape of copper nanocrystals changed from irregular (circular, oblong) to regular(rhombic, triangular, quadrangular, and polygonal) during the processes of fibers growth. The shape and dimension of the catalyst particles have a great influence on the morphology of the fibers. Helical structure is apt to generate over the catalyst particles with small dimension and shape regularity. The shape changes are caused by the changes in surface energy resulting from the acetylene-adsorption on the copper nanocrystals.The XRD, IR, and elemental analysis revealed that the chemical structure of helical fibers was a kind of poly(acetylene)-like polymer, and helical fibers were amorphous. The reaction proceeded mainly by the of acetylene over copper nanocrystals, accompanied by some side reactions. With increasing the reaction temperature, of the C/H ratio of helical fibers increased, but the chemical structure of helical fibers little changed.The as-prepared helical fibers are insulator, and exhibits room temperature (300K) ferromagnetic behavior.
Post about "characterization"
The partially delaminated Stearic Acid Montmorillonite (STA-MMT) was synthesized, using alkaline Ca- montmorillonite and Stearic acid(STA) as raw materials on the condition of circumfluence, water diversion and dispersion in organic solvent. Single factor analysis was performed to investigate the influences of the factors, such as the reaction time, the amount of Stearic acid, the dosage of ethanol in dispersant, the amount of solvent, the droping temperature of the STA solution, the anion exchange capacity(AEC) of the alkaline Ca-montmorillonite, and the partical size of the alkaline Ca-montmorillonite, upon the ignition loss test of organic STA-MMT clay. The optimumcondition was achieved: add dropwise 60mL haxmethylene alkyl solution of Stearic acid(4.50g) into a large beaker, which contains 5.00g 0.076mm alkaline Ca-montmorillonite and 75mL mixed anhydrous solution at 50℃; the anhydrous solution is mixed by haxmethylene alkyl and absolute alcohol with volume ratio of 9: 1. The organic content of the prepared product was about 36.25%.With tools such as XRD, FTIR, SEM, TG/ DTA and DTS, is confirmed that: the Stearic acid anion is intercalated in the layer; the MMT is partially delaminated as the d-spacing enlarges; the dispersibility of STA-MMT reaches the scale of 300nm in the solvent of ethanol. In comparison with montmorillonite modified by cetyltrimethyl ammonium bromide, this partially delaminated Stearic acid montmorillonite has such merits like: better gel properties, larger surface area, smaller partical size and better dispersibility in most of organic dissolvents.Furthermore, using partially delaminated Stearic acid montmorillonite as a precursor, hydrophobic /stearic acid montmorillonite( / STA-MMT) was prepared by introducing hydrophobic wax into the hydrophobic phased interlayer of partially delaminated Stearic acid montmorillonite. Through single-factor analysis, the optimum condition was obtained: at 55℃, add 5.00g wax into a large beaker, which contains 3.00g STA-MMT and 200mL mixed anhydrous solution of haxmethylene alkyl and absolute alcohol ( V_A: V_H=1 : 9), then stir for thermostat reactions over 5 hours. The organic content of the prepared wax/STA-MMT is 71.55%, with 36.30% contributed by wax. XRD and DSC means were used to study the structure and melting point of wax/STA-MMT. Through characterizations is shown that good compatibility exists between STA-MMT and wax; meanwhile the melting point of wax increased by 60.7℃.
Optimization of Geotrichum sp. SYBC WU-3 Fermentation for Lipase Production and the Enzyme Characterization
Lipases are important enzymes universally applied in industries;is significant to screen new resources and to characterize novel s for specific application.A strain of lipase producing microbial was isolated from nature. was morphologically idntified as Geotrichum .sp and termed as Geotrichum sp. SYBC WU-3.The effect of inducing agents and suefactants on the lipase production of Geotrichum sp. SYBC WU-3 was investigated. The results showed that olive oil, nuts composite oil, Tween-20, Tween-80, and TritoonX-100 could promote lipase production by Geotrichum sp. SYBC WU-3, when nut complex oil and TritoonX-100 or olive oil and TritoonX-100 was added to the medium, a new isozyme named as LIP-1 could be induced, the constitutive lipas of Geotrichum sp. SYBC WU-3 was termed as LIP-2.The optimum medium for the yield of lipase was that containing peptone 5 g/L, NaH2PO4 3g/L, nuts oil 250 mL/L, Polyoxyethylene polyglycol ether 25 mL/L. The strain was cultivated at the temperature of 30℃for 72 h. The enzyme activity under the optimal condition was 3.2 folds of that under the condition before optimization.Isozyme LIP-1 and LIP-2 was purified by DEAE-32 chromatography, Sephadex G-100 gel filtration and two-phase extraction. LIP-1 and LIP-2 was purified 15.6 and 22 folds respctively. Their recovery was 11.15 %and 17.9 % respectively.Both LIP-1 and LIP-2 was cold-adapted alkaline lipase. Their optimal pH in 50 mmol/L pH 7.0 Tris-HCl buffer are 9.5. Both of them showed high lipolytic activity from pH 3.0 to 9.0. The optimal catalytic temperature of LIP-1 and LIP-2 was 20℃and 15℃respectively. LIP-1 was labile at 50℃, LIP-2 was labile at 40℃. LIP-1 had stronger ability to hydrolyte long chain fatty acid esters and LIP-2 had high hydrolysis ability to hydrolyte short chain fatty acid esters.
Conjugated linoleic acid (CLA) refers to geometric and positional isomers of linoleic acid (LA) with two conjugated double bonds. Originally discovered as a naturally occurring anticarcinogen, CLA has been subsequently show to lowerrisk, enhance immunity and reduce body fat. Especially the c9, t11-CLA is recognized as the most biologically active isomer. Although methods have been described for the isolation of CLA isomers from chemically synthesized mixtures, the processes are expensive and often do not produce a single isomer at high purity. Some microorganisms such as the , are capable of producing CLA from LA. The mechanism is that the existence of linoleate isomerase enzyme convert linoleic acid to CLA. So the study of linoleate isomerase enzyme has been the focus of considerable research efforts in recent years. ZS2058, which was screened from the Chinese traditional fermented vegetable, has the capacity to convert the LA into CLA. The location of ZS2058 linoleate isomerase and partial of the crude enzyme extract were studied in this paper. The optimum disruption conditions of ultrasonicwave for Lactobacillus plantarum ZS2058 were as follows:power of treatment 400W, time of treatment 7.5min (time for each treatment was 5s, with a 9s interval). After an ultra centrifugation step (150,000×g, 1h, 4℃) to separate membrane from soluble material, 70% of the enzyme activity was detected in the membranous material. And Triton X-100 could increase the enzyme activity in the crude enzyme extract significantly. But NaCl could not increase the crude enzyme activity significantly. These results support the conclusion that Lactobacillus plantarum ZS2058 linoleate isomerase is a membrane-associated protein (integral). The optimum concentration for linoleic acid was determined to be 0.08mg/mL. And 5% glycerol could enhance the stability of the crude enzyme.The optimum saturation of Ammonium sulphate for linoleate isomerase was 30-50%. The anion exchange column was eluted with a NaCl gradient of 0-0.75M, and the linoleate isomerase activity peak was eluted at 0.12M NaCl when the pH value of Tris-HCl buffer was 9.0. The linoleate isomerase was purified by Ammonium sulphate precipitation, anion exchange and size exclusion column chromatography, achieving an overall purification of 8.49-fold and a specific activity of 168.58U/mg. The purified enzyme was a single band of around 66kDa on SDS-PAGE.The optimum temperature for linoleate isomerase activity was about 35℃. And the optimum pH was about 5.5. No external cofactors or energy source were required for catalysis. The effect of the metal-chelators (EDTA and EGTA) and metal ions were not significant. The Km and Vmax for linoleate isomerase were 2.15×10-5mol/L and 3.71×10-9mol/ (min?mg), respectively.
Polyphenol and phytic acid have a more extensive utility in the food industry and other areas. Many literatures about the plant material in the production of the phytic acid andhad been reported. However, and phytic acid are the main anti-nutritional substance in the rapeseed meal. Double low rapeseed had become the bottleneck in the comprehensive utility of rapeseed meal. Therefore, effective and preparation polyphenol and phytic acid from rapeseed meal and enhancement of its bio-activity become the key point in the process of rapeseed meal.In this study, while rapeseed meal in the of polyphenol and phytic acid for innovation, compared with the former extraction step by step, simplified the extraction process, might save the partial process unit for the rapeseed cake deep-processing, and the results of extraction meet the expected demand.In this study, Hubei Xishui Zhayou plant providing the “double low” hybrid strain.Cold pressing meal on the No.4 rapeseed meal for the experiment.The pretreatment immersed with acid ethanol and added a small amount of additives of dodecyl benzene sulphonic acid, and then extracted the phytic acid and polyphenol from rapeseed meal at the same time, and use the response surface to analysis and determine optimum conditions. Using solvent of sodium hydroxide to precipitate the phytic acid, then was purified tthrough ion exchange resins. After the treatment mentioned above, the phytic acid samples was analyzed. The polyphenol,in the precipitation solvent, was extracted by using of organic solvent, and then was purified by macroporous resin to classify to several grades.The level of different sub-components were analyzed. The results are as follows:1. The optimun extraction condition of extracting the phytic acid and polyphenol at the same: The acid ethnol with the additive of dodecyl benzene sulphonic acid was the extraction solvent.Through the single-factor analysis and response surface the optimun extraction conditions was determined: 80 mesh rapeseed cakes, 12.50:1 fluids materials ratio, 54℃, 57minutes, two times extraction, respectively. In this condition, the yields of polyphenol and phytic acid were 2.64% and 4.86%, respectively.2. and of the phytic acid: The phytic acid were precipitated by NaOH soultion. Dissolved by hydrochloric acid, sample concentration was turned to about 4.71mg/ml. Firstly the sample was purified with ion exchange resins D315 as rate of flow 1ml/min, then it was decompressed enriched. Finally it tackled with the processing line of Sodium phytate, getting the production of Sodium phytate with 84.2%. Scaned by UV spectrometer, the phytic acid has maxmum wavelength in 260nm, same with phytic acid standard’s absorption peak.Compared to standard’s HPLC chramatogram, the sample had same retent peak about 4min. so did the infrared map. So it proved they were the same compound.3. purification and of polyphenol: The concentration of crude polyphenol rised by 9.61% through the treatment of petroleum ether and chloroform. Different molecule weight of polyphenol had different polarity. Differet polyphenol with different distribution of molecule weight could been seperated through extraction solvent of ethyl acetate, water, methanol. Raw material could adsorped by macroporous resin. And then the polyphenol was rinsed by 60% ethnol.Compared with polyphenol standard sample, its concentration was as high as 65.48%. Scaned by UV spectrometer, the polyphenol has maxmum wavelength in 280nm, as the tannin. The sample was detected through RP-HPLC, while mobile phase was 30% acetonitrile. the results showed that ethyl acetate grade has earlier retent time thanother grade, aqueous phase secondly and methanol phase thirdly.
Study on Characterization of β-glucosidase from Lotus Seeds and Its Effect on Lotus Leaves Beverage’s Aroma
（EC 18.104.22.168）, a kind of hydrolytic enzyme, is one of the key enzymes which plays an important role in the alcoholic aroma formation of the plant . can hydrolyzeβ-D-glucosidase bond to the non-redox molecule chain’s end accompany with releasing theβ-D-glucose and relative ligands. Recently, many literatures about the research on P-glucosidase has been reported, but little about extracting from aquatic plant. This experiment、primarily, explored the process of , analytic measure of its activity, seperation and purification of , and research its enzymatic property. The beverage, made from lotus leaves and treated withβ-glucosidase, was detected by the HS-SPME and GC-MS ,compared with the non-adding group, to study the impact ofβ-glucosidase’s on effect.Main results are as follow:1 Optimizing activity analysis and method ofβ-glucosidase from lotus seeds.The enzymatic reaction should be performed at 56℃、pH 5.0 in 60min and the testing wavelength ought to be 400nm. Measured by this method,the activity of fresh lotus seeds was 1.78U/g, the the activity changed to 1.26U/g after lotus seeds be dried.The different kinds of buffer and pH has crucial impact on the activity of enzyme during the process of extraction. This experiment found out that the optimum measurement to extract theβ-glucosidase from lotus seeds during the process of extraction, was pH 6.0 citric acid – Na2HPO4 buffer and proper ratio of sample to PVPP was 5:1.2 Seperation and purificationβ-glucosidase from lotus seeds.The range of ammonium sulfate precipitation ofβ-glucosidase in the system was 50%-70% saturated solubility, 87.6% activity ofβ-glucosidase concentrated in this rang. After the sample was separated by ion-exchange chromatography of DAEA-52 cellulose, theβ-glucosidase was purified by 18.28 fold, and specific activity reached to 286.6×10-3U/mg. Through Sephadex G-100 gel filtration chromatography,β-glucosidase, was father purified 32.57 fold with a specific activity of 510.83×10-3U/mg. But after a series of process of purification, the total activity of enzyme decreased sharply, and the yield of enzyme was only 1.29%.3 The property ofβ-glucosidase from lotus seeds.The optimum temperature and pH of activity ofβ-glucosidase was 56℃, 5.0 respectively. The thermo-stability experiment indicated that the enzyme remianed comparitive high activity for 150 mins in 30℃-50℃. The preservation-stability experiement showed thatβ-glucosidase have very well preservation-stability at 4℃, even after half a month possessed high activity about 91%. And pH stability experiment showed that, pH5.0-7.0, theβ-glucosidase had best acivity. When it in the alkalescence environment, the stability and activity of enzyme decreased sharply. Km was 2.281mmol/L, and Vmax was 2.308 U/L. SDS-PAGE electrophoresis indicated thatβ-glucosidase from lotus seeds contained two monomers, the molecule weight was 39.2KDa and 30.1KDa.In the lower concentration environment of Ca2+、Mg2+、Al3+、Zn2+, the ions had little impact on the activity of enzyme. When the concentration of Mg2+ reached to as high as 4.0 mmol/L, it can promote the activity of enzyme conspicuously. But when the concentration Al3+ and Zn2+ rose over 6.0 mmol/L, they could inhibit the activity of enzyme conspicuously. Low concentration of Vc and cysteine-HCl could promote enzyme activity slightly. Sodium chloride and sodium sulfite could inhibit the activity ofβ-glucosidase. More higher concentration, more inbihition effect could be observed.4 The function ofβ-glucosidase on The optimum extracting condition,using HS-SPME, from , the extracting time was 60min; extracting temperature was 50℃Headspace volume was 40ml. The GC-MS results demonstrated that the main flavor in the lotus leaves beverage was aldehyde, ketone, alcohol, their proportion were 19.69%、16.24%、6.25% in the whole odor material. The proportion of flavor in the total odor components ,in the lotus leaves beverage, were enhanced after the treatment ofβ-glucosidase to 12%. And the relatively content of aldehyde, ketone, alcohol in the whole aroma, change to 17.18%、16.54%、8.82% respectively. Meanwhile,β-glucosidase had major impact on the content of Ester, its relatively content had increased from 3.21% to 7.64%.The flavor substances of lotus leaves beverage ,added withβ-glucosidase, had critically been enhanced with merit of more flavorful and tender aroma.
Magnetic nano material is a new material appeared in the 1980′s. Due to the effect of the nano materials not only small size effect, quantum size effect, surface effect and macroscopic quantum tunnel effect, but the magnetic function such as magnetic recording, magnetic separation, wave adsorbing and so on. Therefore,as a new material,magnetic nano-carbon powders occupy an important position in the field of electronic,information, agriculture, aerospace, chemistry and biomedical etc, and have been one of the hotspots in the current research field on materials.At present, there are several methods to prepare magnetic particles such as precipitation method, hydrothermal method, micro-emulsion and reverse micro-emulsion method,, chemical vapor deposition method and evaporation condensation method and so on. In all these methods, due to its advantages of mild reaction conditions, not high demand of the equipment technology, good system chemical homogeneity, high purity of prepared product, uniform distribution of particle size and narrow size distribution, has became the primary means in preparing nano-magnetic material at home and abroad.In this paper, The were prepared by , in which the coal tar pitch was first oxidized into aqua-mesophase pitch （ ） by mixtures of concentrated sulfuric acid and nitric acid, and then the was dissolved in aqueous solution of ammonia hydroxide to form the carbonaceous hydrogel, in which various ferric salt solution was added to form composite Fe/C gel. then, the Fe/C gel directly exchanged with ethanol to remove water and dried at room temperature. After carbonization at certain temperatures, the were obtained. The research includes that using hot pumping filtration to replace the previous cold method to improve the process conditions in AMP preparation. Moreover, the influence of stirring velocity on the yields and properties of AMP were studied. The various composite Fe/C gels were gotten by add different ferrous salt using the sol-gel method, the Fe/C gel was dried at room temperature and carbonized at different temperatures to get the magnetic nano carbon powders. The AMP, the primary magnetic nano-carbon powders and their heat-treated products with different Fe content were characterized by FT-IR, TG, XRD, TEM, M-H loops and wave absorbing performance test.The results show that the reactions such as nitration, oxidation and sulfonation mainly happened during the reactions of coal tar pitch with mixing acids. The yield of AMP and the efficiency have been greatly increased because of using the hot pumping filtration. The particle size of magnetic nano carbon powders prepared by ferric chloride and ferric sulfate is 5nm.There is a turbostratic carbon structure in all the magnetic nano carbon powders, and the Fe element exists as the form ofγ-Fe2O3 in the powders treatment at low temperature. In high temperature treated powders the Fe element exists as form of a-Fe、rhombic Fe2O3、γ-Fe2O3 and Fe3C. The pyrolysis process of original magnetic nano-carbon powders can be divided into five stages, including removal of ethanol and water, pre-pyrolysis, heavy pyrolysis, construction of carbon structure and decomposition of Fe（OH）3, rearrangement of carbon structure with deoxidization of Fe2O3. The magnetic nano-carbon powders belong to the soft magnetic materials and have a good property of magnetic response, The saturation magnetization became larger with the Fe content increased. The coercivity is basically the same of magnetic nano carbon powders with different Fe content. The prepared magnetic nano carbon powders with low Fe content have a better reflective properties of microwaves than the powders that with high Fe content during the frequency of 8-18GZ. Choose five different organic materials to prepare coated magnetic nano carbon powders, was made by the tartartic acid and, but the particle size is large.
In recent years, hollow microspheres have attracted much attention and can be used in many fileds because of their special properties, such as low densities, high surface areas, good heat stability and larger inner space. In this paper, we used the template method. Our work consisted of two parts: first, we synthesized the silica hollow microspheres through CaCO3 template, and then silica ands were fabricated through octylamine （OA） template. The SEM, TEM, XRD, FTIR and nitrogen adsorption methods have been employed to characterize morphologies and structures of silica hollow microspheres （SHMS）, and the factors which have effects on the fabrication of the samples have also been investigated.First we studied the of the silica hollow microspheres by two different s （one is nanosized, the other is microsized）. By using CaCO3 as template and CTAB as the mesoporous-directing agents, mesoporous SHMS were synthesized via sol-gel method. The SHMS prepared with nanosized CaCO3 have anomaly shapes and higher surface areas （842m2/g）. The SHMS prepared with microsized CaCO3 have a good roundness and are well-dispersed, but with lower surface areas （554.01m2/g）. At the same time, we also investigated the effects of CTAB contents and temperatures on the structures of SHMS. The results showed that SHMS had integrated structures when prepared with higher CTAB contents and the mesopore structures turn more orderly. The BET areas of SHMS were lager with the increase of the temperatures.Then we studied the preparation of the silica and s on OA template. By using OA as template and hydrochloric acid as catalyst, silica and s with a good quality were fabricated rapidly. As-synthesized SHMS were between 10μm and 30μm , with a high surface area of 997.9m2/g, a mean pore diameter of 1.6nm, and a mean pore volume of 0.77m2/g （the BJH results）. The particle size of SHMS increased with the reaction temperature, but the samples intended to aggregate when the temperature was above 50℃. A higher stirring speed would improve the degree of homogeneity. The mean diameter of the Si/Al composite oxide hollow microspheres was 10μm and the content of Al was 4.34%. Because of the low content of Al, resulted that the XRD and FTIR patterns of Si/Al composite oxide hollow microspheres were nearly the same as SHMS.
Isolation of Silicate Mineral-solubilizing Bacteria and the Interaction between Silicate Mineral and the Bacteria
Microorganisms are the earliest life forms on the planet,have been more than 30 billion years,they are widely distributed on the near-surface or surface of the earth.The dissolution,migration and precipitation of the mineral in element entironment are all dependent on the effect of microorganisms.On the contrary,the minerals also impact the survive and multiply of microbes.So the study of the interaction of minerals and microbes has become a hotspot of environmental mineralogy.In present study,our investigations on the interaction of bacteria and silicate minerals could enrich the theory of earth biological evolution,especially the role of bacteria in the silicate mineral weathering and the forming.Two silicate mineral-solubilizing bacterial strain Q28 and Q32 was isolated from the surfaces of weathered feldspar and identified as Rhizobium spp based on the physiological and biochemical characteristics and 16S rDNA gene sequence analysis.Both of the strains can fix nitrogen,produce indole acetic acid（IAA）,siderophores,or surfactant.The results of the influence of the temperature,pH,osmolality,heavy metals and antibiotics on the growth of the strains showed that The optimum growth conditions of strains Q28,Q32 were:temperature 28℃,pH 7-9.The median lethal dose of Strain Q28 is Pb2+(1500 mg·L-1)、Cr2+(5 mg·L-1)、Cu2+(5 mg·L-1)、Ni2+(10 mg·L-1)、Zn2+(1000 mg·L-1)、Cd2+(10 mg·L-1)、Str(50 mg·L-1)、Tc(2 mg·L-1)、Rif(1 mg·L-1)、Kn(100 mg·L-1)、Ap(200 mg·L-1);The median lethal dose of Strain Q32 is Pb2+(2000 mg·L-1)、Cr2+(5 mg·L-1)、Cu2+(10 mg·L-1)、Ni2+(20 mg·L-1)、Zn2+(2000 mg·L-1)、Cd2+(25 mg·L-1).、Str(100 mg·L-1)、Tc(50 mg·L-1)、Rif(1 mg·L-1)、Kn(100 mg·L-1)、Ap(200 mg·L-1).Both of Q28 and Q32 were sensitive to rifampicin.Q32-gfp with gfp marker gene were gained by tri-parental mating.Studies showed that the gfp gene could steadily exist in the labeled strains and did not affect their copper-solubilizing ability.Colonization experiment showed the labeled strains Q32-gfp, could colonize on the surface of feldspar and biotite. The study on the interaction bacteria with mineral shows that strains Q28 and Q32 can liberate silicon in kinds of silicate minerals,such as feldspar、biotite、dolomite and phlogopite;the mineral can promote bacterial biomass increase,bacterial cell shape deformation,Strain promote the secretion ofs and organic acids, s and can lead to changes in the structure,enhance complexation;strains of mineral particle size of 40-100 head decomposition ability not significantly different; strains under natural conditions can also decomposition Minerals,but the effects of decomposition than flask experiment.Strain Q28,Q32 of the metabolites of organic acid and can erode potassium feldspar and biotite,polysaccharides in which play a major role,and organic acid and polysaccharide complex effects than the organic acid and polysaccharide alone.
Catalase can decompose H2O2 into H2O and O2 effectively. Physiologicallyacts as a regulator of H2O2 levels in organelles and protect organism from the damage of reactive oxygen species. Catalases from various sources are utilized in several applications, such as diseases diagnosis and removal of hydrogen peroxide in food sterilization. Catalase is used in removal of hydrogen peroxide in the textile pretreatment as a substitute for high-temperature water washing and using chemical reducing agents.In this study, we investigated the methods for , purification and of a from Bacillus subtilis WSHDZ-01. And be intended to improve the thermostability of the catalse by using additives. The main results were given as follows:(1) The Bacillus subtilis WSHDZ-01 cells were permeabilized by the method of chloroform shock. Experimental results showed that, under the biomass condition of 0.01 g DCW, addition of 20μL chloroform, treating 30min, and permeation in water for 60 min at 37℃, the release of was up to 85 % of total.(2) The purification was performed with a three-step procedure consisting of ethanol precipitation, DEAE ion exchange and hydrophobic interaction chromatography, and finally achieved a 6.8-fold-purifying over the crude extract. SDS-PAGE of the purified catalase revealed the final presence of a single band at an apparent molecular mass of 63 kD. The native enzyme showed the typical Sort band appearing at 405 nm, which indicated that the purified catalase is a heme-containing enzyme. The apparent Km value for enzyme activity on H2O2 was calculated to be 26.87 mmol/L. The activity of this catalase was not reduced by dithionite but was strongly inhibited by cyanide, azide and 3-amino-1, 2, 4-triazole (the specific inhibitor to monofunctional catalase). No peroxidase activity of this enzyme was detected when using p-phenylenediamine as an electron donor. Therefore, suggested that this catalase belonged to monofunctional catalases.(3) Besides, this catalase was thermosensitive, and its activity exhibited pH-independently between pH 5-10 but showed a sharp maximum at pH 11-12. No activity was lost when the enzyme was incubated at 25℃and pH 11 for 60 min. The catalase reacted best at 55℃,and is quite stable when maintained at below 50℃.(4) Sugars, polyols, metal ions, anions and other chemical materials were added in catalase solution to improve its stability. The remaining activity of CAT when maintained at 60℃for 15 min was increased to 80 % in the presence of 500 mmol/L sodium acetate, 500 mmol/L sodium sulfate, 50 % ethylene glycol and 50 % PEG..(5) According to the study, the deactivation process at different temperatures of the native CAT is followed the first inactivation order. But it is followed second inactivation order in the presence of sodium acetate and sodium sulfate. Through the study of the thermodynamic properties, we found that the thermostability of native catalase was poor at high temperature. It was improved greatly in the presence of the two additives, but it showed great variation at different temperatures as well as in the absence of them.