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1.
L—苹果酸产生菌Aspergillus flavus HLD—12产酸条件的研究   总被引:3,自引:0,他引:3  
本文报道HLD-12菌株发酵L-苹果酸的特点.研究了碳源、氮源、温度、CaCO3、金属离子和促进剂等因素对HLD-12菌株苹果酸发酵的影响,确定了HLD-12菌株的最佳产酸条件,其中最适碳源为8%的葡萄糖,最适氮源为0.15%的(NH4)2SO4,CaCO3浓度为7%。生物素和丙氨酸在一定浓度范围内能显著提高HLD-12菌株的产酸水平。  相似文献   

2.
用海藻酸钙包埋黑曲霉Ax-6分生孢子制成固定化孢子,在发酵培养基中进行表面培养和间歇式培养生产柠檬酸,固定化孢子在14%蔗糖为单一碳源的培养基中,pH为3.8,温度为35℃下表面培养13d,柠檬酸产量为65.53g.L^-1,在相同条件下,间歇式培养31d,柠檬酸的产量保持在52.15-81.02g.l^-1,第2批柠檬酸产量高达81.02g.L^-1,而游离孢子仅保持发酵17d。第2批柠檬酸最高  相似文献   

3.
青春双歧杆菌和乳链球菌混合发酵的研究   总被引:1,自引:0,他引:1  
对人体有益的肠道菌(青春双歧杆菌BA菌株和乳链球菌SL菌株)的双菌混合发酵进行了研究,选择了双菌混合发酵的最佳碳源,发酵周期,以及混合发酵的两种菌接种量的比例,在常温下保存300d,活菌体在1×106个/mL左右.并采用双菌混合发酵产物对小鼠进行了急性毒性测定,观察其对小鼠免疫器官重量的影响.  相似文献   

4.
麦角菌(Clavicepspurpurea(Fr.)Tul.ATCC20019)发酵生产麦角隐亭.培养时间1~23d内,产减量逐步增加,第23d菌丝体和发酵液中的减总量达198μg/mL.发酵4~6d,培养基中的无机磷基本耗尽,产减量开始增加.用第4d产碱期菌丝体接种,碱产量从常规接种112.5μg/mL增加到157.8μg/mL.发酵中期补加磷酸二氢钾,菌丝体生长量略有增加,但抑制麦角隐亭的合成.提取的样品经沉淀反应、薄层层析、红外谱分析,鉴定为α-麦角隐亭的酒石酸盐.  相似文献   

5.
赤霉菌J126是赤素产孢新菌株,其主要产物为赤霉酸,薄层层析显示还能产GA4和GA7摇瓶培养研究表明,以木薯粉,硝酸铵为碳氮源的适宜培养基等条件下发酵,总赤霉素产率达678.8mg.L^-1,可作为新菌株选育的良好菌种。  相似文献   

6.
细胞转化法生产L—苹果酸的研究   总被引:3,自引:1,他引:2  
报道普通变形杆菌细胞转化法生产L-苹果酸的研究,探讨菌体培养和转化反应条件等因素对菌体延胡索酸活性的影响、菌体酶的热性和PH稳定性。确定最佳工艺条件和酶的稳定性条件分别为:菌体培养时间72h,转化反应温35℃,底物转化液PH7.0,转化反应时间3h;温度≤35℃,pH6.0-7.8,菌体经过10批次转化反应后,其延胡索酸酶活性仍很稳定,酶活保存率达87.0%。  相似文献   

7.
芽胞杆菌EV23基本为组成性地合成碱性纤维素酶,以不同碳源生长时酶合成水平差别不显著。葡萄糖(Glu)、果糖等易代谢碳源在ρ=10g·L-1时,不但不抑制酶的合成,还相对地促进酶的合成。以Glu为碳源培养,ρ=40g·L-1时酶合成水平最高,ρ≥50g·L-1时酶合成才有部分被阻遏。ATP、三羧酸循环中间物对酶合成有一定的阻遏作用,表明EV23碱性纤维素酶的抗阻遏合成是有一定限度的。  相似文献   

8.
温度和光照等因素对荸荠试管球茎形成的影响   总被引:3,自引:0,他引:3  
“桂林马蹄”和“余杭大红袍”的荸蔼茎尖接种在MS+KT0.1mg.L^-1地培养基上15d后,诱导出的试管苗在MS+6-BA2.0mg.L^-1+NAA1.0mg.La^-1培养基上增殖培养25d后,再经60d培养可诱导出试管球茎,供试两品种试管球茎形成的最适增减其分别为MS+6-BA1.0mg.L^-1+蔗糖90g.L^-1和MS+6-BA0.8mg.L^-1+蔗糖90g.L^-1,最适培养条件  相似文献   

9.
着重讨论了葡萄糖对L-天冬酰胺酶发酵过程的影响,并对其发酵动力学特性进行了分析。采用自动流加葡萄糖控制发酵pH的工艺,可使L-天冬酰胺酶活力达到64u/ml,比添加葡萄糖的摇瓶发酵提高了146%。流加葡萄糖控制pH的L-天冬酰胺酶发酵是生长相关的;维持2~5mg/ml和1.2~1.4mg/ml的葡萄糖浓度,可分别使比生长速率和比产酶速率达到0.81/h和1200u/g.h。  相似文献   

10.
菌种储藏对一株头孢霉菌产DHA的影响   总被引:2,自引:0,他引:2  
将一株头孢霉菌(Cephalosporium.sp.)斜面菌种分别在20.4和-20℃d,将菌种分别经活化和不活化后转接入液本PDA培养基中发酵发现DHA(Docosahex-aenoic acid.22:6)产量和储藏时间、储藏温度、发酵前菌种是否转接活化有关系,在-20℃储藏的菌种,DHA最高产量可达27.86mg/L,此时每克干菌丝中DHA含量为4.26mg,生物量为6.54g/L;在4℃储  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
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。  相似文献   

14.
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.  相似文献   

15.
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-  相似文献   

16.
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-  相似文献   

17.
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  相似文献   

18.
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  相似文献   

19.
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  相似文献   

20.
<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  相似文献   

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