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    25 December 2006, Volume 34 Issue 12
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    Environment Science & Technology
    Effect of Alternative Aerobic and Anaerobic Composting on Heavy Metals in Municipal Sewage Sludge
    Zhou Shao-qi Lu Wei-dong
    2006, 34(12):  1-4. 
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    In order to investigate the variations of contents and chemical forms of heavy metals in the municipal sewage sludge during the alternative aerobic and anaerobic composting, municipal sewage sludge was mixed with municipal organic garbage to carry out a 602day alternative aerobic and anaerobic composting tryout. In the experiment, the moisture content and the C /N ratio were respectively controlled at about 60% and 30～40. The results indicate that (1) the contents of Cu, Ni, Cd, Cr and Pb all decrease, while the content of Zn slightly increases; (2) the contents of these metals are all lower than the sewage sludge indices set by the state for agronomic use; (3) the distributions of chemical forms of these heavy metals greatly change after the composting, especially, the proportions and contents of Cu, Ni, Cd, Cr and Pb in changeable form decrease obviously; and (4) the proportion of Zn in changeable form decreases, while the content slightly increases. These results indicate that the alternative aerobic and anaerobic composting can p revent the soil and water from being contaminated by heavy metals when municipal sewage sludge and organic garbage are adop ted for in agronomic use.

    Effect of Void Status in Eco-Concrete for Planting on Plant Growth
    Hu Yong-you Hu Chun-ming Xie Lei Guo Qing-wei Wang Xin Zhang Tai-ping Zheng Bing-hui
    2006, 34(12):  5-9. 
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    In order to p rovide more references for the suitability determination of eco2concrete for p lanting, four kinds of eco2concreteswith different void statuseswere fabricated, in which Paspalum notatum Flugge was p lanted,and the growth of the p lantwas observed. Then, several items of the p lantwere measured, including the content of proline in the p lant, the ability of the roots in absorbing nutrition and the p roportion of active part of the roots. The results show that (1) besides the void ratio, the average aperture also exert significant influence on the suitability of the p lant; (2) the p lant growsmuch better in the eco2concrete with a larger void ratio and a bigger average aperture; and (3) Paspalum notatum Flugge grows better in the eco2concrete with a void ratio of 39. 45% and an average aperture of 6. 4mm than in the eco2concrete with a void ratio of 36% and an average aperture of 4mm.

    Operation Optimization of O3-BAC Advanced Treatment Process for Drinking Water
    Lu Shao-ming Wang Ning Yang Li
    2006, 34(12):  10-14. 
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    A pilot-scale experiment of O3-biological activated carbon (O3-BAC) advanced treatment process was carried out for the surface water at levels Ⅱ～Ⅲ in the Dongjiang River, Guangzhou. The removal rules of the con-tamination in the water were then investigated. In the experiment, two processes, namely Process I-pre-ozone +conventional treatment p rocess +O3 +BAC and Process Ⅱ-p re-ozone + conventional treatment p rocess +BAC were adop ted to perform a contrast test. The experimental results were finally compared with the practical data of the Nanzhou Drinking-Water Treatment Plant. Some suggestions for the optimization of O3-BAC process were made in accordance with the quality of the raw water. The results of the p ilot2scale experiment show that, in order to ensure the drinking-water quality, Process Ⅱ should be adop ted when the raw water is of a CODMn of no more than 3. 0mg/L and a NH3-N content of no more than 1. 0mg/L, and that ProcessⅠshould be adopted when the raw wa-ter is of a CODMn ofmore than 3. 5mg/L or a NH3-N content ofmore than 1. 5mg/L. The p ractical operation results of the Nanzhou Drinking2Water Treatment Plant also reveal that Processes Ⅰand Ⅱ can be alternately adop ted in accordance with the quality of the raw water.

    Screening and Microbial Diversity Analysis of High-Eff iciency Phenol-Degradation Bacter ia
    Su Jun-feng Ma Fang Wang Qiang Hou Ning Gao Shan-shan Wang Hong-yu
    2006, 34(12):  15-19. 
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    In order to reveal the differences in the microbial diversity of the bacilli stock cultured in different sub-strates aswell as culture high2efficiency phenol2degradation bacteria, the V3 section during the 16S rRNA was used as the target to investigate and compare the biodiversities of bacteria isolates respectively cultured in three different isolation substrates, namely the self-prepared SJ substrate, the LB substrate and the YEB substrate. The results show that SJ substrate ismore suitable for the isolation of bacteria with higher microbial diversity than LB and YEB substrates, and that the three strains of high2efficiency phenol-degradation bacteria screened by SJ substrate are all of a total-phenol removal rate ofmore than 99%. Moreover, according to the phylogenic tree established bymeans of physiological and biochemical app raisals and 16S rDNA sequencing, the three strains are respectively Aero-monas, Bacillus and Acinetobacter.

    Electronics, Communication & Automation Technology
    A Critical Review of the Artides,Authors and Citations in the Journal of South China University of Technology(Natural Science Edition)(2000-2006)
    Yan Zhi-sen
    2006, 34(12):  120-124. 
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    By using the biblio·metrics method,18 issues of Journal of South China Universtiy of Technology(Natural Science Edition)(Journal of SCUT for short),including all the 12 issues of 2005 and the six No.1 issues from 2000 to 2006,were quantitatively an alyzed.The results were then compared with those in the literature.It is indicated that(1)Journal of SCUT is a high-quality joumal with a collaboration rate of 94.1% and a collaboration degree of 3.17;(2)in this joumal,70.9% theses are supported by foundation fund,38.9% authors are professors,61.8% authors are doctors or post doctorates.28.8% authors are at the age of less than 30,an d 44.1% authors are at the age between 31 and 40;and(3)for each article,the average reference number is 8.23,in which 59.9% are written in English,and 65.3% are cited from journals,which indicate that the jouil~ is of a high-level citation.

    Chemistry,Chemical & Energy Engineering
    Preparation of MFI-Type Zeolite M embrane for Pervaporation Separation of Xylene Isomers
    Yuan Wen-hui Luo Yi-ke Li Li
    2006, 34(12):  63-67. 
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    MFI-type zeolite membranes were prepared on-alumina support dip-coated with seed layer by means of the secondary growth method,with silica sol without organic template as the promoter.The properties of the pre-pared zeolite membranes were then characterized by XRD,SEM and gas permeation experiments.Th e pervapora-tion separation of pure xylene isomer an d its binary mixtures through the prepared MFI·-type membranes was also in-vestigated.Th e results show that the membranes were perm eable for P-xylene isomers but not for other isomers at 5O℃ for 10 h,with a decreasing pervaporation flux order of p-xylene>m-xylene>o-xylene;(2)the separation factors of p-/o-xylene and p-/m-xylene of both single and binary mixtures reach 67 and 46,29 and 42,respectively;(3)the fhlxes ofp-xylene and o-xylene are respectively 7. 41 ×10- 4and 0. 11 ×10- 4 mol/ (m2 ·s) ;and(4)the fluxes ofp-xylene an d o-xylene of binary mixtures are respectively 3. 58 ×10- 4and 0. 086 ×10- 4 mol/ (m2 ·s).All these results indicate that the prepared MFI-type zeolite membran e is suitable for the pervaporation separation of xylene isomers.

    Catalyst for Autothermal Reforming of M ethane to Produce Hydrogen
    Cai Xiu-lan Dong Xin-fa Lin Wei-ming
    2006, 34(12):  68-71. 
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    The efects of some additives and their dosages on the autothermal reforming of methane to produce hy-drogen were investigated using a fixed—bed mieroreaetor.Th e additives include rare e l metals such as La and Ce and transitional metals such as Zr and Cu．The results show that(1)the addition of Ce or Zr greatly improves the catalytic performance of Ni catalyst;(2)the catalytic performance of the catalyst promoted by both Ce and Zr in
    diferent mass ratio is obviously diferent from that ofthe catalyst promoted only by Ce or Zr;(3)as compared with Ni/Zr20Al80Oδand Ni/Ce30Al70Oδ catalysts,Ni/Zr10 Ce20 Al70 Oδ results in all improved H2 yield;and(4)when Cu is added in Ni/Zr10 Ce20 Al70 Oδ ,the new—formed catalyst Ni/Cu3 Zr10Ce20Al67Oδis of the best catalytic performance,th a CH4 conversion of 100% ,a H2,yield of 72.9% and a H2 selectivity of 100% at 750℃ .

    Activation Energy of Phenol Desorption from Modified Activated Carbon
    Pan Hong-yan Li Zhong Xia Qi-bin Xi Hong-xia
    2006, 34(12):  72-77. 
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    This paper aims to investigate the efects of different metal ions loaded on activated carbon(AC)on the activation energy of phenol desorption.In the investigation,six kinds of metal ions were respectively loaded on the AC surface by means of impregnation.Then,the activation energies of phenol desorption from the six kinds of modified activated carbons were determined using the temperature-programmed desorption(TPD)technique,and the efects of metal-ion loading on the desorption activation energy were an alyzed and discussed with the help of Hard Soft Acid Base(HSAB)principle.The results show that the activation energies of phenol desorption from Al(9I)/AC,Mg (II)/AC,Fe(Ⅲ)/AC and Ca(II)/AC are all larger than those from the original AC,while the activation energies of phenol desorption from Ag(I)/AC and Cu(II)/AC are smaller.According to the HSAB pfin-ciple,phe-nol belongs to hard base,the loadings of hard acid ions AI ,Mg ,Fe an d Ca on AC lead to an increase in the local acid hardness of AC surface,thus improving the adsorption for phenol.However,since Ag an d Cu are respectively soft acid an d borderline acid ions,the loadings of Ag an d Cu on AC result in a decrease in the local acid hardness of AC surface,thereby,the surface adsorption for phenol becomes weak to some extent.

    Preparation and PhotocatalyticTitania with Urea asActivity of Nitrogen-DopedNitrogen Source
    Qin Hao-li Gu Guo-bang Liu Song Li Jin-jing
    2006, 34(12):  78-82. 
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    In order to expand the optical response of titania into the visible-light region，nitrogen·doped titania po w-ders with urea as the nitrogen source were prepared by sol-gel method in mild conditions.The prepared samples were then characterized using XRD,TEM,UV-Vis difuse reflectance spectrophotometer and X-ray photoelectron spectroscopy.Moreover,the photocatalytic activities of the sam ples in the visible-light region were tested,and the influences of calcination temperature and nitrogen content on the photocatalytic activity were investigated.Th e re-suits indicate that(1)the doping of nitrogen leads to an increase in optical absorption intensity in the visible-light region.which results in a high visible-light photocatalytic activity with nitrogen-doped titania in the decolouration of methyl orange;(2)with the increase in calcination temperature,the nitrogen content decreases,the crystallite size enlarges,and the visible-light photocatalytic activity weakens;and(3)there exists an optimum N/Ti proportion for the catalysts calcined at 400 ℃ ,which results in the highest visible-light photoctalytic activity。

    Dynamics and M echanism of Ultrasonic-Assisted Emulsion Polymerization of Vinyl Acetate
    Hou Hui-Yu Tu Wei-Ping
    2006, 34(12):  83-87. 
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    In order to improve the reaction rate and monomer conversion of the polymerization of vinyl acetate,PO-tassium persulfate and sodium dodecyl sulfate were used respectively as the initiator an d the emulsifier to produce poly-vinyl acetate by means of pre-emulsification intermittent polymerization.The efects of ultrasonic power,initiator dosage,emulsifier dosage,monomer dosage and reaction temperature on the reaction rate of the ultrasonic-assis-ted emulsion polymerization were then studied.Furtherm ore,the mechan ism of the ultrasonic-assisted emulsion-po ly-merization was discussed,and the approaches of ultrasonic to afect the polymerization were analyzed.Th e results show that,in the experimental conditions of the present study,ultrasonic radiation helps to improve the polymerization rate an d the monomer conversion,and may result in an apparent activation energy of 51.55 kJ/mol.

    Acetylation of Schizophyllan and Corresponding Spectroscopic Analysis
    Zhou Lin Guo Si-yuan Zheng Bi-sheng Li Lin
    2006, 34(12):  88-91. 
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    Acetylated schizophyllan(Ac·SPG)at milligram level with diferent degree of substitution(DS)was synthesized with dimethyl sulfoxide as the solvent in pyridine·acetic anhydride system.The spectral characters of the samples before and after the acetylation were then analyzed.The infrared spectrum of Ac.SPG reveals tlle C﹦O stretching vibration of ester bond in the range of 1735～1729 em-1.a weak band of C﹦O stretching at 1251 em and a slight move of C﹦O stretching vibration to high wavenumber with tlle increase in acetic an.hydride content．Th e UV spectrum of Ac·SPG reveals a weak C﹦O absorption in the range of 252～272 nm.The chemical shifts at 2.1 and 5.1 in HNMR spectrum prove that there exists O-acetylation methyl.Moreover,there.suits of GPC for samples before and after the acetylation indicate that the relative molecular mass of Ac-SPG ob-viously decreases,also the polydispersity,as compared with the native SPG.It is a pity that no formula can be es-tablished to calculate the DS of Ac·-SPG according to the infrared an d ultraviolet spec~a due to the nonlinearity be -DS and the corresponding typical absorbanee.

    Characterization and Magnetic Resonance of Magnetic Chitosan Microsphere
    Kou Ling-mei Li Bing Guo Si-yuan Li Lin Jie-zhen
    2006, 34(12):  92-95,100. 
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    Magnetic chitosan microspheres were synthesized by means of the reverse-·phase suspension cross-linking technique,with glutaraldehyde as the cross-linker and Fe3O4as the magnetic core.The morphology,particle size an d chemical structure of the prepared microspheres were then characterized using the digital optical microscope,the laser granularity meter and the PnR.an d the magnetic resonance ofthe microspheres Was investigated using the atom-absorbing spectrophotometer,the magnetic balance and the adjustable magnetic field.The results demonstrate
    that the prepared magnetic chitosan microspheres are well-shaped spheres with a diameter from 50 to 200 μm,in which Fe3O4 particles disperse uniformly,and that,when the mi crospheres in an exte .rnal magnetic field are ofa dia-meter of less than 280μm,its magnetic susceptibility and sedimentation rate increase with the size.It is indicated that the prepared magnetic chitosan microspheres are of excelent magnetic resonan ce.

    Carboxylation of Sugarcane Bagasse and Characterization of Carboxylated Sugarcane Bagasse
    Liu Chuan-fu Sun Run-cang Ye Jun Zhang Ai-ping
    2006, 34(12):  96-100. 
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    Maleic anhydride and phthalic anhydride were used to carboxylate unprocessed sugarcane bagasse after ultrasonic radiation,an d the efects of ultrasonic radiation time,the reaction temperature and the anhydride dosage on the carboxylation yield were investigated.The yield was then compared with that of the sugarcan e bagasse treated with succinic anhydride.Experimental results show that the carboxylation yield reaches the maximum with an ultrasonic radiation for 30 min at the reaction temperature of 90℃.Characterization results of the carboxylated sugarcane bagasse by FTIR.CP/MAS 13CNMR spectroscopy and thermal an alysis indicate that there occurs the esteriflcation ofthe hydroxyl groups at C2 and C3 positions inthe cellulose,and that the therm al stability ofthe modified sugarcane bagasse decreases due to the esterification.

    Separation and Characteristics of Enzymatic/Acidolysis Lignin
    Wang Shao-guang Wu Shu-bin Guo Yi-li Guo Xiu-qiang
    2006, 34(12):  101-104. 
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    A novel high·eficiency method named Enzymatic/Acidolysis was introduced to isolate lignin from kraft pulp and raw fiber materials,with the lignin named enzymatic/acidolysis lignin(EMAL)being isolated.The main factors that afect the enzymatic hydrolysis and acid hydrolysis stages dudng the isolation were then discussed in detail.It is revEMALed that the yield of EMAL is 2～3 times that of the traditional milled.wood lignin(MWL),and that EMAL is of a higher purity than MWL.It is also indicated by an alysis that there is no remarkable diference in structure between the EMAL from wood materials and the corresponding MW L. Ihe experiments also demonstrate that,as compared with the coresponding MWL,the EMAL from non·wood materials is of similar purity but faifly higher yield.

    Preparation of Nano-Sized Calcium Carbonate Using Rotating Packed Bed with Homocentric Ring Discs as Filling
    Pan Zhao-qun Yu Le Zhang Ya-jun Deng Xian-he Tian Dong-lei
    2006, 34(12):  105-109. 
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    Nano-sized calcium carbonate with the diameter between 20 to 30 Bin was prepared using the rotating packed bed with homocentric ring discs as the filing,and the factors which influence the production of the llano-sized calcium carbonate were investigated.Experimental results indicate that(1)the diam eter of the product de-creases with the increase in the rotational speed,the gas flux,the CO2 content in the gas phase an d the dosage of the crystal style controller;(2)when Ca(OH)2 concentration is fairly low,the diameter decreases with the in-crease in Ca(OH)2 concentration;(3)the reaction time decreases with the increase in the rotational speed,the gas flux and the CO2 content,but increases with the dosage of the crystal style controler;and(4)in the optimal preparation conditions,that is,a rotational speed of 1 100r/min,a CO2 content of 40%(volume fraction)and a dosage of the crystal style controler of 0.5%.the product is of small size an d the reaction time cost is faifly low.

    Process Simulation and Enlarged Capacity Analysis of Main Fractionation Column in Delayed Coking Unit
    Wang Chun-hua Chen Qing-lin Hua Ben Chen Zi-jian
    2006, 34(12):  110-114. 
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    This paper aims at the strategies to simulate the distillation process in a delayed coking unit(DCU)by using the simulation software of SimSci/PRO Ⅱ.Since the components of the reaction vapor in the DCU fractionation column are unknown and there are imbalanced trays at the bottom of the column,the compo sition of the high-temperature oil and gas feedstock in the fractionation column is inversely conjectured according to the composition of the products,an d the whole column is divided into two sections,namely the bottom heat-exchange section and the rectifying section.Then, the Grayson-Streed property choice method is adopted to simulate the fractionation process.Th e simulated results.which are consistent with the on-site ope rational data,indicate that there is an obvious fluctuant flowrate of the gas and the liquid along the trays.Moreover,a hydraulics calculation is carried out for.the main fractionation column,and a tray-load performan ce diagram is drawn .Th e results show that weeping ex-ists at most trays,which call be solved by plugging up some holes in the weeping trays.Finally,in accordance with the production requirements in the refinery,a simulation and a hydraulics calculation are perform ed for the fr~ tionation column whose processing capacity is increased by 22% .It is thus concluded that a partial revam ping of the fracfionation column can meet the requirements of production with enlarged capacity.

    Numerical Simulation of Natural Heat Convection on Vertical Plate Reinforced with Longitudinal Vortex
    Yangg Ze-liang Wu Xin-ying
    2006, 34(12):  115-119. 
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    Arranging longitudinal vortex generators is an efective non-source method to enhan ce heat convection.In this paper,the PHEONICS calculating software is used to numerically simulate the natural heat convection on the vertical plate reinforced with longitudinal vortex generators.The simulated results accord well with the experimental results.Th en,a simulation investigation into the geometrical factors an d the generator arrangement is conducted.It is indicated that(1)the longitudinal space will afect the heat convection when the longitudinal vortex generators ale of a multi-low arrangement;(2)when is 35 mm,the average heat exchange coeficient reaches the maximum value;(3)in the sanle geometrical condition,the stagger arrangement oflongitudinal vortex generators results in a better total heat exchange efect than the in-line arrangement;and(4)as to the stagger arrangement of longitudinal vortex generators with a winglet width of 20 ram,both the winglet height and the transverse space influence the heat
    exchange efect,and the optimal winglet height and transverse space are respectively 20mm and 90mm.

    Biological Engineering
    Identification of Tetragenococcus halophilus Isolated from Chinese Soy Sauce Koji
    Luo L i-xin Lü Li Pan Li Qiu Zhen-yu Wang Bin
    2006, 34(12):  20-24. 
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    A haloph ilous lactic acid cocci strain w as isolated from the trad itional Chinese soy sauce koj.i The morphology, the physio log ical and b iochem ica l characterist ics and the 16S rDNA sequence of the screened strain were then analyzed, based on which the taxonomic status of the screened strain was established to lay a foundation for the role analysis of the screened strain in soy sauce brewage. The results show that the screened strain is tetrad-formed,Gram-positive, non-motile and catalase-negative, which can produce acid from glucose without gas formation, and that the yield of lactic acid produced by the screened strain reaches 2. 2% at a N aCl content of 18% . Moreover,the phylogenetic analysis of the screened strain based on its 16S rDNA sequence demonstrate that the strain is of the closestre lativity to Tetragenococcus halophilus, which basically means that the screened strain belongs to Tetragenococcus halophilus.

    Cloning of Reteplase Gene and Expression of the Gene in Pichia methanolica
    Gang Jie Jiang Cheng-ying Du Lian-xiang Lu Fu-ping Guo Hong-jie L i Di Liu Hai-yang
    2006, 34(12):  25-29,50. 
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    The cloning of Retep lase ( r-PA) gene of tissue-type plasminogen activator ( t-PA) mutant was first carried out, and the gene was extracellularly expressed in Pichia methanolica. Next, the gene-encoding Reteplase ( r-PA) was cloned to pMD18-T vector by PCR using recombinant strain Trichoderma reesei 306 chromosome DNA as the template. Then, a sequence determination was conducted, indicating that the cloned gene sequence is of a length of 1. 1 kb and an identity of 99. 91% or 100% respectively with the published Reteplase gene or amino acids. Moreover, the secreted expression plasmid pMETαA-r-PA of Pichia methanolica was not only constructed and digested with PacⅠ but also transformed into Pichia methanolica PMAD16 by means of electroporation. The positive transformants that integrate r-PA genes in their genomes were thus obtained, which was verified by PCR technique and Mut phenotype determination. After the shake-flask culture and the induced expression with methanol as the only carbon source, the extracellular Reteplase ( r-PA) activity was up to 27. 93mol/ ( s·L).

    Enantioselectivity of Candida rugosa Lipase-Catalyzed Interesterification of(R,S)-2-Octano
    Shi Xian-ai Lou Wen-yong Zong Min-hua Guo Yang-hao Meng Chun
    2006, 34(12):  30-34. 
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    The enantioselectivity of Candida ru．gosa lipase(CRL)-catalyzed asymmetric interesterification of(R,S)-2-octanol respectively in organic solvent,reverse micelle or ionic liquid was investigated.The results indicate significant influences of reaction medium and acyl donor on the enantioselectivity of CRL.In toluene,the enantio-selective rate E for CRL-catalyzed interesterification of(R,S)-2-octanol wi山ethyl chloroacetate is faifly hiSh(E=92.2).In reverse micelle CTAB/butanol/isooctane/H2O,CRL displays rather high enantioselective rate(E»100)when vinyl acetate is used as the acyl donor.However,in ionic liquid [ bmim ] PF6,CRL shows little enantio-selectivity．

    Determination of Peptidase System of Microorganisms in Ripening of Chinese Sufu
    Yang Zuo-yi Li Li Liang Shi-zhong Yang Xiao-quan
    2006, 34(12):  35-40. 
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    Synthetical substrates were used to test the peptidase activities of diferent microorganisms,including Brevibacterium DH1,JS3,GH4,DG6 and Yeast SCY1,JSBB2 isolated in the ripening of sufu in South China.The intracellular an d extracellular peptidase systems of these strains were also studied.Experimental results show that the endopeptidase activities of the strains are fairly high,and that the Leu-aminopeptidaso ,Arg-aminopepti-dase,dipeptidase and carboxypeptidase activities prominently exhibit in the isolated strains.As to the two yeasts,it is of hish Glu-aminopeptidase and Lys-aminopeptidase activities as well as prolific dipeptidaso an d carboxypeptidase activities.

    Enzymatic Preparation of ACEIP Based on Structure Information
    Zhu Zhi-wei Tu Xiao-ke Zeng Qing-xiao Ruan Zheng Zhang De-cong
    2006, 34(12):  41-46. 
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    The aim of this research is to investigate the enzymatic preparation of angiotensin Ⅰ-converting enzyme in-hibitory peptide(ACEIP)on the basis of the structure information analysis and by choosing enzymes tII preferen-tial specificity,thus preliminarily giving a directional and controlled enzymolysis technology according to the struc-ture information．In the investigation,the structure information of 1 1 selected angiotensin Ⅰ-converting enzyme in-hibitors was analyzed by means of the Complete Neglect of Diferential Overlap(CNDO).The results indicate that the oligopeptide possesses high inhibitory activity to angiotensin I-converting enzyme(ACE)when it is of residues Pro,Trp,Met,Phe and Lys in C·term inal position an d when residues Asp an d Glu in N-terminal position.Th en,the enzymatic preparation of ACEIP from tilapia meat was conducted using enzymes with preferential specificity.Th e hydrolysate,in which Thr-Cys,Asp-Trp an d Glu·Met were found,was finally extracted and analyzed.The re-suits accord with the theoretical results,which preliminarily shows the feasibility of the directional and controlled enzymatic technology based on the structure inform ation.

    Efect of Dynamic M agnetic Field on M icroorganisms
    Xu xi-lin Guo Si-Yuan Li Lin
    2006, 34(12):  47-50. 
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    This paper investigates the survival law of microorganisms under the action of dynamic magnetic field (DMF).The research results show that(1)few yeast cells survive under the action of DMF;(2)DMF has a greater effect on mildew than on yeast,and about 80% of mildew spores cannot sprout due to the action of DMF;and(3)most ofthe bacteria do not survive under the action of DMF although the efect of DMF varies with the spe-cies;and(4)under the action of DMF,the cell structure can be damaged,and some cell components of microorganisms,for example,the nucleic acid,can leak from the cell to the broth．It is thus concluded that DMF treat-ment can be applied to the control of microorganism in industry.

    Effect of Ultrasonic Radiation on Escherichia coil Membrane
    Lu Qun Qiu Tai-qi
    2006, 34(12):  51-54,57. 
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    Three fluorescent dyestufs，namely FDA,Rh1 23 and DCFH-DA,were used to stain Escherichia coli (E.coli),and the fluorescence spectrophotometer,the fluorescence microscopy and the TEM were adopted to observe‘ the membrane alteration of E.col radiated by ultrasonic.Th e results indicate that fluorescent probe is feasi-ble in the determ ination of the alteration of E.col membrane,and that,after be ing radiated by ultrasonic at 300 W and 25 kHz f0r 90 s,the cell maintains an integrated structure,but the double molecule layer of the membrane be -comes blurry,with apertures on the surface and with the content material penetrating to the oumide.Moreover,the membrane potential decreases by 26.7% while,in contrast,the memb rane perm eability increases by 12.7% ,with the ROS level significan tly improved.

    Investigation into Kinetics of Enzymatic Preparation of Peptides from Gallus Protein
    Pe Zhi-ying Chen Zhong Long Biao Qiu Li-ping Chen Yong-gen
    2006, 34(12):  55-58. 
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    The one-order thermal inactivation of papain for the enzymatic preparation of peptides from Ga/lus protein was investigated with the Gallus protein as the substrate.Th e K value under the mimesis of enzymatic preparation was also investigated.Then,by taking into account the competitive inhibition from both the substrate and the pro-duct.the corresponding enzymatic kinetic models were established．Moreover,the kinetic constants of the enzyma-tic preparation at 70℃ were respectively determ ined asK d=0. 0113m in- 1,  Km=5. 70×10- 3mol/L and  K cat=1. 5898min- 1.The kinetic models describing the hydroxylation degree and the hydrolysis velocity were finally de-term ined．

    Distribution of Lignin in Cell Wall of Salix gordejecii Fiber
    Xu Feng Zhong Xin-chun Lu qi Sun Run-cang
    2006, 34(12):  59-62. 
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    The distribution of lignin in the cell wall of Salix gordejecii fiber and its efect on pulping and papermaking were studied.The ultrastmcture of the cell wall of lix gordejecii fiber and the distribution of lignin in the cell wall were then determined using TEM .scanning electron microscopy combined with energy dispersive X-ray analysis(SEM.EDXA)and confocal laser scanning microscopy(CLSM.The TEM images show that the cell wall of Salix gordejecii fiber is typically divided into three layers,namely the middle lamellar,the primary wall and the secondary wall that includes the outer.the middle and the inner layers,The CLSM images reveal that the distribution of lignin in the cell wall layers is not uniforill.folowing a decreasing o er of the cell comer,the middle lam ellar and the secondary wall.and that the lignin concentration in the vessel is larger than that in the fiber cell.Moreover.the SEM.EDXA results indicate that the lignin concentration in the cell comer,the middle lam elar and the middle layer ofthe secondary wall is in a ratio of 2.15:1.32:1.

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