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1.
枯草芽孢杆菌培养液水解鱼蛋白质制备蛋白胨的初步研究   总被引:1,自引:0,他引:1  
对枯草芽孢杆菌胞外蛋白酶的产生条件及其培养液水解鱼蛋白质制备蛋白胨进行了初步研究.结果表明,适宜枯草芽孢杆菌产蛋白酶的培养基初始pH值7.0、培养温度30℃、250mL三角瓶中的装液量为60mL,培养时间为24h;用枯草芽孢杆菌培养液为蛋白酶源水解蛋白质时,应控制反应体系的温度为55℃,pH9.0,加入低浓度的Mg^2+、Ca^2+并去除Cu^2+、Fe^3+、Pb^2+和Ag^+,对枯草芽孢杆菌产酶有促进作用.用枯草芽孢杆菌培养液分别水解鳕鱼粉和罗非鱼,蛋白质制备蛋白胨的得率分别为13.95%和14.96%,与目前的工业水平基本相当.  相似文献   

2.
酶解鱿鱼蛋白的制备   总被引:3,自引:0,他引:3  
探讨了中性蛋白酶、木瓜蛋白酶、胃蛋白酶、风味蛋白、酶菠萝蛋白酶以及复合蛋白酶对鱿鱼蛋白的酶解效果.实验结果表明,在相同水解条件下,复合酶对鱿鱼蛋白的水解效果优于单酶,确定了木瓜蛋白酶和中性蛋白酶为水解鱿鱼蛋白的适宜水解酶,两种酶量的比例为1:1,正交实验得出最佳水解条件为:温度50℃、pH7、时间8 h、加酶量6 000IU/g.  相似文献   

3.
对蚝油的酶水解工艺条件进行初步研究。结果表明:酶水解的最佳条件为酸性蛋白酶,酶水解温度50℃,超始pH2.5,酶用量5000u/g,酶水解时间4-5h。  相似文献   

4.
在蛋白酶水解法制备香菇酱的工艺中,首先研究了超声波对原料进行细胞破碎处理的操作条件,采用正交实验设计对影响蛋白酶水解效果的条件进行了选择优化。结果表明,超声波处理的最佳功率为200W、最佳处理时间为30min,蛋白酶水解的最佳工艺条件为酶解温度40℃、pH值4.5、酶用量1%、酶解时间60min,在此工艺条件下香菇酱的氨基酸含量为0.88%。  相似文献   

5.
研究了中性蛋白酶和木瓜蛋白酶对鹅血液的水解作用,并分析了酶用量、温度、时间、pH值等因素对鹅血酶水解的影响。结果表明,双酶水解效果较好,确定了其最适宜的酶解条件:中性蛋白酶,酶底物浓度比(E/S)为4000U/g,pH值为7.0,温度为55℃,时间为5h;木瓜蛋白酶,酶底物浓度比(E/S)为6000U/g,pH值为7.5,温度为50℃,时间为4h。  相似文献   

6.
酶法水解乳清蛋白过程的优化   总被引:1,自引:0,他引:1  
以浓缩乳清蛋白为原料,选择碱性蛋白酶(Alcalase)水解乳清蛋白。分析了pH、温度、酶和底物比(E/S)和反应时间等因素对乳清蛋白水解的影响。通过响应面法分析,确定了碱性蛋白酶(Alcalase)酶解乳清蛋白的最佳水解条件为:pH8.5、反应温度55℃、酶和底物比0.05。水解3.0h,水解度为19.34%。  相似文献   

7.
pH渐变条件下双酶协同水解大豆蛋白   总被引:2,自引:0,他引:2  
研究了在没有外加碱的pH渐变条件下.用枯草杆菌碱性蛋白酶(Alcalase 2.4L,酶活力2.4AU/g)和黑曲霉酸性蛋白酶(酶活力3000u/g)双酶协同水解从大豆蛋白制备寡肽(10个氨基酸以下的肽)水解物的可行性.考察了单酶单因素水解条件、双酶加入方式对大豆蛋白降解率和蛋白质水解度的影响,并在此基础上通过正交试验进一步优化出双酶一次性投料方案下水解大豆蛋白的最佳条件:水解温度为60℃.碱性蛋白酶加入量为每g蛋白15μL,酸性蛋白酶加入量为6%,底物浓度为40g/L,水解时间为18h.在上述最佳条件下,大豆蛋白的降解率可达76%,蛋白质的水解度可达26%,水解物中相对分子质量小于1350的寡肽达到了66%.结果表明,在不外加碱的条件下,采用双酶协同水解方法能够显著提高大豆蛋白降解率以及蛋白质水解度.  相似文献   

8.
研究胃蛋白酶对红豆蛋白的水解工艺.考察酶浓度、pH、温度、水解时间等因素对红豆蛋白水解度的影响.结果表明:制备的胃蛋白酶能够较好地水解红豆蛋白,其最佳水解工艺为:温度40℃、酶浓度7U/g干蛋白、pH1.5、水解时间4h,其最佳水解度为30.97%.  相似文献   

9.
研究了脂肪酶对油酯污布除油率的影响。结果表明,脂肪酶Lip在含量为40-100u/mL,洗涤溶液pH为9.0,洗涤温度为20-40℃,洗涤时间为20-30min时去污效果最佳。Lip与AES,TX-10或Sav配伍使用有良好的配伍去污作用,而与LAS的配伍去污效果不佳。添加酶稳定剂可以保存酶在洗涤过程中的相对活性,增强脂肪酶的去污作用。  相似文献   

10.
采用蒸煮法、脂肪酶法、乙醚法对鲢肉进行脱脂.并比较不同酶制剂对脱脂鲢肉的水解效果.试验结果表明。脂肪酶法的脱脂效果最好,其脱脂率为98.11%.根据水解度及感官品尝指标,从5种酶中优选出复合蛋白酶为脱脂鱼肉的最佳水解酶.并通过正交实验确定该酶的最佳水解工艺条件:pH6.5,温度55℃,酶最3000U/g.蛋白质,底物浓度(鱼肉:水)1:3.  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.
<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   

20.
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