产纤维素酶新菌株的筛选及其产酶特性研究

【目的】筛选分离新的纤维素酶产酶菌株,并对其生长特性和产酶特性进行研究。【方法】从堆肥样品中分离得到一株产纤维素酶菌株,定名为CP1,利用16SrRNA序列对比和Biolog微生物鉴定系统进行鉴定。通过测定菌株生长速率确定其最适生长条件。采用CMC发酵培养基进行纤维素酶的研究,确定其产酶曲线。测定粗酶液最适作用温度和pH值,热稳定性和金属离子对其影响。【结果】经鉴定该菌株为梭形芽孢杆菌(Lysinibacillus fusiformis),其最适生长温度为30℃,最适生长pH值为6。在含CMC-Na的培养基培养,该菌株的生长与产酶同步进行,培养48h菌株生长量达到最大,培养液的CMC酶活力同时达到最大值,为0.46U/mL。该菌株所产的纤维素酶既有酸性CMC酶活力,又有碱性CMC酶活力,并以碱性CMC酶为主,酸性CMC酶的活力只有碱性CMC酶的71.4%。其酸性CMC酶的最适作用pH值为6.0,碱性CMC酶的最适作用pH值为8.0。另外,该菌株所产碱性CMC酶活的最适作用温度为40~50℃,而且0.5%的Cu2+使其酶活降低45%。【结论】菌株CP1为首次报道的梭形芽孢杆菌产纤维素酶新菌株,具有独特的酸碱性环境下的纤维素酶活力。     

植酸酶液体发酵条件及酶学性质的研究

植酸酶产生菌黑曲霉 90 3(Aspergillusniger)的最适产酶条件 :初始pH5 .0～ 6 .5 ,温度2 9± 1℃ ,培养时间 4d ,2 5 0ml三角瓶发酵液的装量为 5 0ml,一定量的Fe2 +和Mn2 +对产酶有促进作用 ;酶的最适作用pH为 5 .5～ 6 .0 ,最适作用温度为 37℃ ,该酶在 pH3.0～ 7.0 ,温度 30～ 5 0℃时稳定性较好。     

纤维素降解菌的筛选与诱变育种

采用羧甲基纤维素(CMC)平板初筛和50℃培养,筛选到一株纤维素酶活力较高的耐高温霉菌MY菌株,其CMC培养基最适pH为6.0,培养温度为40℃,最佳产酶时间为5d.以MY菌株为出发菌株,分别采用紫外线和硫酸二乙酯诱变,以透明圈直径与菌落直径的比值(HC值)提高30%以上或菌落形态发生明显变异为筛选指标,共筛选到97株突变株;通过测定粗酶液CMC酶活力,从中筛选出29株CMC酶活力提高30%以上的菌株;结合突变菌株的传代稳定性实验,最后筛选得到1株性能优良的霉菌MY004突变株,其CMC酶活力比原始菌株MY提高了80.6%.     

产脂肪酶假丝酵母的筛选及其研究

从武汉油污样中分离获得一株高产脂肪酶酶的假丝酵母R－2．发酵研究表明,最适培养基为蛋白胨20g/L,蔗糖10g/L,橄榄油5g/L,(NH4)2SO41g/L,MgSO4.7H2O1g/L,K2HPOR1g/L和吐温－801g/L,最适产酶条件为30℃,初始pH7．0,转速200r/min,培养32h ,最高产酶活力达到1437u/mL,酶作用最适温度40℃,最适pH7.5。     

一株产高温纤维素酶真菌的筛选、鉴定及酶学性质研究

从造纸厂污泥中获得一株产高温纤维素酶的真菌XM5,经形态学和ITS序列分析,鉴定其为土曲霉(Aspergillus terreus).在稻草液体发酵培养基中,土曲霉XM5所产纤维素酶的合成模式为同步合成型.酶学性质研究表明,该纤维素酶的最适作用温度是65℃,在80℃下保温2 h活力残留40%以上,最适作用pH为4.0,在pH4.0～7.0内较稳定,实验结果表明,该菌株所产纤维素酶具有较好的温度稳定性和pH稳定性.     

碱性脂肪酶产生菌--扩展青霉K40原生质体的制备和再生

采用 0 .6%纤维素酶加 0 .6%蜗牛酶的混合酶由扩展青霉 K4 0中获得大量的原生质体 ,并比较了菌龄、二硫苏糖醇 ( DTT)预处理方式、酶解时间、温度、 p H、培养基成分及稳定剂等因素对原生质体的形成和再生的作用 .选出制备原生质体的最适条件 :0 .6%纤维素酶 +0 .6%蜗牛酶 ,在 0 .6mol/L Na Cl+0 .3 %Ca Cl2 ,DTT预处理 0 .5h,菌龄为 1 9～ 2 0 h,p H 5.4 ,2 8℃酶解 3～ 3 .5h,原生质体产量可达 2 .3 6× 1 0 7个/ml,实现再生 ,再生率达 70 %～ 80 % .并对原生质体的释放和再生方式进行跟踪观察     

纤维素降解菌的筛选与诱变育种

采用羧甲基纤维素（CMC）平板初筛和50℃培养, 筛选到一株纤维素酶活力较高的耐高温霉菌MY菌株, 其CMC培养基最适pH为6.0, 培养温度为40℃, 最佳产酶时间为5d. 以MY菌株为出发菌株, 分别采用紫外线和硫酸二乙酯诱变, 以透明圈直径与菌落直径的比值（HC值）提高30%以上或菌落形态发生明显变异为筛选指标, 共筛选到97株突变株; 通过测定粗酶液CMC酶活力, 从中筛选出29株CMC酶活力提高30%以上的菌株; 结合突变菌株的传代稳定性实验, 最后筛选得到1株性能优良的霉菌MY004突变株, 其CMC酶活力比原始菌株MY提高了80.6%.     

产纤维素酶海洋细菌的筛选和酶学性质的初步研究

从病烂的海洋植物中分离到一株高产纤维素酶的菌株TX-12,革兰氏阴性,经鉴定为噬纤维菌属(Cellulophaga sp.)中的一个种.该菌株在温度25℃、培养基起始pH 8.0条件下培养56 h产生碱性纤维素酶活力高达354.8 U/mL.酶学性质初步研究显示,TX-12产生的纤维素酶最适反应pH值为8.0,最适反应温度为60℃,在0～100℃酶活均能保持最高酶活的70%以上.酶液在100℃时仍具有较高的稳定性.Fe2+、Cu2+、Mn2+对酶反应有一定促进作用,Hg2+和Pb2+对酶反应有强烈的抑制作用.     

芽孢杆菌嗜热蛋白酶的性质研究

对芽孢杆菌嗜热蛋白酶的性质进行了研究.该酶的分子量为32kD,最适作用pH为9 0,最适作用温度为85℃,具有良好的pH稳定性(在60℃时,pH稳定范围为6 0～11 0;在80℃时,pH稳定范围为6 0～10 0)和热稳定性(90℃时酶活的半衰期为20min).钙离子和有机溶剂能提高该酶的热稳定性,而EDTA和PMSF则能抑制该酶活性.     

产中性纤维素酶真菌产酶条件的优化

研究了碳源、氮源、接种量、培养时间、培养温度、培养基初始pH等条件对产中性纤维素酶真菌菌株瓶霉菌（Phialophora sp．z8）产酶的影响．结果表明：该菌株产中性纤维素酶的适宜碳源为1％稻草粉加1％可溶性淀粉,最适氮源为0．2％的（NH4）2SO4加0．1％的牛肉膏,接种量为5％,培养时间为72h,培养温度为28℃,培养基初始pH为6～7．在最适宜的条件下,培养液中内切葡聚糖酶活力可达到2．95IU／mL,而天然纤维素酶活力和滤纸酶活力却很低。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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