克雷伯氏菌产物耐受突变株的发酵工艺

克雷伯氏菌(Klebsiella pneumoniae)是1,3-丙二醇(1,3-PD)生产菌。研究了经60Co诱变获得的一株产物耐受突变株KpA6010进行了发酵初期供氧时间、供氧与否和发酵过程中后期维持甘油浓度对1,3-PD生产及副产物形成影响。结果显示,采取全厌氧发酵和中后期维持甘油质量浓度20 g/L的工艺对1,3-PD生产有利。5 L罐全程厌氧补料分批培养结果表明,1,3-PD的产量、摩尔得率和生产强度分别达到70.81 g/L、0.649和2.083 g/(L.h),较出发菌分别提高了54.3%、52.0%和50.7%。     

NaCS/PDMDAAC微囊化肺炎克雷伯氏菌发酵产1,3-丙二醇

研究一种新型的生物微胶囊体系--NaCS/PDMDAAC,包埋肺炎克雷伯氏菌(K. Pneumoniae ZJU 5205)产1,3-丙二醇.比较不同初始菌体包埋量、胶囊/发酵液体积、发酵液pH值、初始甘油质量浓度等对微囊化细胞发酵结果的影响.结果表明,将细胞种子液稀释5倍后包埋,当胶囊与发酵液的体积比为1∶2、初始pH值为7、初始甘油质量浓度为60 g·L-1时,得到较好的发酵结果.考察肺炎克雷伯氏菌在囊内的生长曲线,以及底物和产物质量浓度随发酵时间的变化,发现由于胶囊引起的扩散限制,可以持续维持囊内较低的底物质量浓度,从而部分克服高质量浓度底物对菌体生长和生成产物的抑制.     

乙酸对1，3-丙二醇发酵的影响

考察了克雷伯氏菌发酵生产1,3-丙二醇过程中，乙酸对发酵过程的影响。结果表明，在发酵初始培养基中加入微量的乙酸能够提高1，3－丙二醇的产量，但乙酸的添加会影响菌体生长，造成发酵液的菌体吸光度A下降。通过实验确定了乙酸的最优添加质量浓度为0.6g/L，此时1,3-丙二醇质量浓度为8.46g/L，转化率为0.62；在此浓度乙酸初始培养基中添加1.2g/L葡萄糖作为辅助底物将甘油转化率提高到0.66。     

微生物转化法生产1,3-丙二醇的研究进展

综述微生物转化法生产1,3-丙二醇(1,3-PD)的研究进展,包括发酵菌种和发酵工艺等.生物转化法生产1,3-PD与化学法相比,具有选择性好、转化率高、分离纯化简单、无污染、利用可再生资源等优点.要使生物转化法生产1,3-PD能与化学法竞争,在提高1,3-PD发酵生产水平的同时,必须有效降低生产成本.以生物柴油副产物废甘油为发酵底物生产1,3-PD,可大大降低1,3-PD生产成本,同时解决废甘油高附加值利用的问题,延长产业链.但存在的问题是废甘油成分复杂,抑制了微生物的生长和代谢.     

西索米星分批发酵过程动力学模型

采用伊尼奥小单孢菌F003为产生菌的西索米星发酵过程具有典型的非生长耦联特征,西索米星浓度大于0.50 g/L将明显抑制产物合成.建立了符合不同时期微生物代谢特性的西索米星分批发酵动力学模型,并对模型参数进行了估计和回归,模型拟合偏差平方和≤6%,模型能很好地描述西索米星发酵过程菌体的生长、底物的消耗和产物的合成.菌体生长期动力学模型参数μm、KS、KX、m分别为:0.058 h-1、4.046 g/L、0.433 g/g、0.0001 g/(g.h);产物合成期动力学模型参数μm、KX、K2、N、YX、YP、m分别为:0.058 h-1、60.556 g/g、1.198 g/(g.h)、0.606、0.090 g/g、0.095 g/g、0.00173 g/(g.h).验证实验表明,所建立的模型能较好地预测初始淀粉浓度为50.0~70.0 g/L时西索米星的发酵过程特性.     

Galactomyces reessii转化β-甲基丁酸生产β-羟基-β-甲基丁酸

Galactomycesreessii可将 β-甲基丁酸 ( MBA)转化为 β-羟基 - β-甲基丁酸 ( HMB)。摇瓶实验表明发酵过程中提供生长因子的酵母萃取物浓度以 3 g/L较适宜。高浓度钠、铵离子对菌体生长有抑制作用 ,为保证转化 MBA所需 p H可采用混合碱 ( Na OH、KOH、NH4 OH)来调节 ,以防止单一阳离子浓度过高对菌体生长和产物形成的抑制。MBA对菌体生长有明显的抑制作用 ,1 0 g/L的MBA可使菌体浓度减少 3 0 %。分批补料发酵中 ,连续流加葡萄糖和 MBA,控制发酵液中葡萄糖浓度不超过 3 g/L,MBA浓度不超过 4g/L ,1 0 2 h时 HMB浓度达 2 9.0 g/L ,转化率达 5 7.3 % ,HMB平均生产率达 0 .0 98g/( L· h)。     

微生物转化苯乙酮酸合成R-(-)- 扁桃酸

考察了酵母菌株FD11b不对称还原苯乙酮酸生产R-(-)-扁桃酸的重复使用性能.菌株FD11b在持续6批次(14 d)的还原反应中,一直保持着较高的催化还原活性,且目标产物R-(-)-扁桃酸的对映体过量值(e.e.值)均高于96.5%.在30 L发酵罐上进行Fed-Batch放大试验,当菌体浓度(细胞干重,以下同)为12.5 g/L,底物苯乙酮酸浓度控制在20~30 mmol/L时,还原反应49 h,产物浓度可达125 mmol/L,产物得率为96.1%,e.e.值为98.5%.     

Rhodococcus rhodochrous tg1-A6腈水解酶催化3-氰基吡啶合成烟酸的研究

利用高产腈水解酶的菌株Rhodococcus rhodochrous tg1-A6催化3-氰基吡啶合成烟酸,实验结果表明,腈水解酶的最适底物浓度为130mmol/L,最适催化温度为55℃,最适pH值为pH7.0.经过15h连续补加底物3-氰基吡啶,反应体系中产物烟酸的浓度可达到165.2g/L.在产物浓度累积不高的情况下,菌体经过7批次(共67h)的催化,烟酸的最终质量浓度累计可达到529g/L.     

类人胶原蛋白基因工程菌诱导后比生长速率优化

目的优化类人胶原蛋白基因工程菌高温诱导后的比生长速率。方法通过分析不同比生长速率下发酵液中菌体浓度、类人胶原蛋白浓度、细胞得率系数(YX/S)、产物得率系数(YP/S)的变化,确定诱导后的最佳比生长速率。结果当比生长速率为0.04～0.05h-1,细胞浓度和类人胶原蛋白的浓度分别可达69.5g/L(DCW)和13.8g/L。结论诱导后的比生长速率对细胞生长、类人胶原蛋白的合成均产生显著性影响。     

微生物间歇发酵生产1,3-丙二醇过程辨识与优化

以肺炎杆菌转化甘油生成1,3-丙二醇（1,3-PD）的过程为研究体系,根据微生物间歇培养过程的特征及动态行为,建立了简化的间歇发酵过程的非线性动力系统及其参数辨识模型,论述了动力系统与辨识问题解的存在性,并求得最优辨识参数．以初始底物浓度、菌种浓度及发酵时间为控制变量,以1,3-PD的生产强度为性能指标,建立了非线性系统的最优控制模型,针对实际算例求得最优解,为1,3-PD的产业化生产设计提供理论指导．     

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.     

Features of Women's language

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.     

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     

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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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has