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1.
报道了链霉菌(Streptomyces sp.108)固定化细胞制备的最适条件。初始底物(美伐他汀)浓度300mg/L,间接补加底物总浓度达到800mg/L时,普伐他汀产量为495mg/L,转化率为60%。在底物浓度为300mg/L时重复发酵3次,500mg/L时重复发酵2次,转化率分别达50.5%和53%。  相似文献   

2.
组培条件对何首乌愈伤组织诱导及生长的影响   总被引:6,自引:0,他引:6  
为了寻找适合何首乌愈伤组织诱导与生长的培养条件,本文考察了愈伤组织形成的比率,分析了取样时间、光照条件、培养基中2,4-D、6BA和IBA的浓度对愈伤组织诱导和生长的影响。实验表明,在黑暗中,在添加有1.5mg/L2,4-D,1mg/L 6BA和0.5mg/L BA的MS培养基上,夏季取样的茎段,愈伤组织诱导率可达100%。  相似文献   

3.
郑桂兰  陈小明  王洪钟 《江西科学》2007,25(5):565-568,610
原发酵条件中的底物浓度过低,致使发酵液中的产物浓度不高,就提高底物浓度后的其它发酵条件进行了调整,通过正交实验,获得了最佳的发酵培养基配方,最后通过50 L放大发酵获得了成功,发酵液中产物浓度可达3 619 mg/L.  相似文献   

4.
利用油菜萝卜胞质不育恢复材料测交F4代种子,在附加各种不同激素浓度组合的MS培养基上访导丛生芽、生根及愈伤组织诱导,结果表明:在MS培养基中添加1.0mg/L6—BA_0.1mg/L NAA对诱导丛生芽有较好的效果,l/2MS培养基对小芽生根效果最好,在MS培养基中添加0.5mg/L 8-BA 0.1mg/L NAA 0.25mg/L GA3 0.1mg/L 2,4-D对诱导愈伤组织效果最好.  相似文献   

5.
研究了适合于工业化生产的猪心肌乳酸脱氢酶的初步提取工艺,经硫酸铵分级沉淀得到酶的比活为86.5U/mg,再经DEAE离子交换层析比活可达525.0U/mg,酶活总收率为54.5%.并对酶促反应的最适条件进行了研究,其最适反应pH为7.6~7.8,最适反应底物浓度分别为NADH5mg/mL和丙酮酸钠25mmol/L。  相似文献   

6.
雷斯青霉转化左旋乙基甾烯双酮15α-羟基化反应工艺研究   总被引:1,自引:0,他引:1  
对雷斯青霉(Penicillium raistrickii)微生物转化左旋乙基甾烯双酮15α-羟基化反应的培养基组成和转化条件进行优化.结果表明:优化后最佳培养基组分为葡萄糖30g/L,玉米浆20g/L,NaNO3 2g/L,KH2PI4 1g/L,K2HPO4 2g/L,MgSO4 0.5g/L,FeSO4 0.02g/L,KCl 0.5g/L;最适转化条件为接种量10%,初始pH7.5,摇瓶装量50mL,转化温度28℃,投料量0.2%,投料时间30h,转化时间60h,底物添加方式为底物超声粉碎后加4%V醇和1.5%吐温80溶解.在此条件下。摇瓶转化率可达70%以上。  相似文献   

7.
对雷斯青霉(Penicillium raistrickii)微生物转化左旋乙基甾烯双酮15α-羟基化反应的培养基组成和转化条件进行优化.结果表明:优化后最佳培养基组分为葡萄糖30g/L,玉米浆20g/L,NaNO3 2g/L,KH2P O41g/L,K2HP O42g/L,MgSO40.5g/L,FeSO4 0.02 g/L,KCl 0.5 g/L;最适转化条件为接种量10%,初始pH7.5,摇瓶装量50 mL,转化温度28℃,投料量0.2%,投料时间30h,转化时间60h,底物添加方式为底物超声粉碎后加4%甲醇和1.5%吐温80溶解.在此条件下,摇瓶转化率可达70%以上.  相似文献   

8.
以碳布为阴阳极材料,乙酸钠为底物,MnO_2@graphene为阴极催化剂构建空气阴极单室微生物燃料电池(MFC),研究了阳极液pH、阳极底物初始COD浓度、MFC运行温度等因素对MFC输出电压和产电功率的影响﹒研究结果表明,阳极液pH对MFC产电性能影响最大,而阳极底物初始COD浓度影响最小﹒在阳极液pH为8、MFC运行温度为308 K和阳极底物初始COD浓度为800 mg/L时MFC的产电性能和污水处理最佳﹒在此条件下,MFC对污水中COD的降解率可达98.4%,输出电压和产电功率密度分别可达0.813 V和2 046.9mW/m~2,说明以MnO_2@graphene为阴极催化剂的MFC具有较好的产电性能和污水处理效能﹒  相似文献   

9.
将油莱0guCMS与诸葛菜属间杂种田交一代(BC1),在MS附加不同激素浓度的基本培养基上诱导丛生芽.结果发现,MS+1.5mg/L 6—BA 0.15mg/L NAA对诱导丛生芽有较好的效果,丛生芽增殖系数可达3.2.小芽生根培养基以MS 0.1mg/L NAA的效果较好.  相似文献   

10.
蒲公英试管培养中芽形成的研究   总被引:2,自引:0,他引:2  
应用组织培养技术,探讨不同外植体、生长调节剂及pH对蒲公英芽诱导形成的影响。结果表明:以茎尖作为外植体芽诱导率最高,可达95%,35d时,每个外植体所产生的芽数达5个以上,叶片次之,茎段较低;MS培养基中添加0.05—5mg/L6-BA或KT,对芽形成具有促进作用,其中6-BA2mg/L的用量效果最优,浓度大于5mg/L则抑制芽形成;6-BA和KT分别与NAA或IAA结合使用时比单独使用6-BA和KT效果更为显著,其最佳的浓度比例为2:1;最优组合为2mg/L6-BA 1mg/L IAA;pH以5.8为宜。  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.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
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   

16.
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   

17.
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   

18.
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   

19.
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   

20.
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   

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