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1.
克鲁维酵母Y-85菊粉酶的研究   总被引:2,自引:4,他引:2  
菊粉酶产生菌株─—克鲁维酵母Y-85在15L罐中进行产酶发酵,培养24h,发酵液中菊粉酶的总活力可达1032u/ml,其中胞壁酶活768u/ml,占总酶活的74%。用含半胱氨酸的缓冲液提取胞壁酶,酶的回收率达88%,比活力可达1008u/mg.酶作用于菊糖的最适pH为4.5,最适温度为50℃,在50℃以下和pH4~8稳定,金属离子Ag ̄+、Hg ̄(2+)对酶有强烈的抑制作用,PCMB对酶也有明显的抑制作用。该酶可水解菊糖,棉子糖和蔗糖等多种底物,能快速将菊芋抽提液中的菊糖水解成果糖,适合用于以菊芋为原料的高果糖浆生产。  相似文献   

2.
产菊糖酶菌株的选育及其营养需求的研究   总被引:2,自引:0,他引:2  
从47种真菌中筛选中2株能分解菊芋菊糖并产生低聚果糖的菌株,摇瓶发酵的适当条件为,基质含菊糖提取物4%,蛋白胨0.3%,尿素0.2%,温度31℃,摇床转速200r/min,培养时间42h,最高产菊糖酶达240.3u/mL,颗糖相对于菊糖的转化率最高为81.4%,直接用固体菊芋粉接种培养所选菌种,加水保温,分解菊芋粉中的菊糖生产低聚果糖,在适宜的营养条件下,低聚果糖相对于菊芋粉的最高转化率为14%。  相似文献   

3.
克鲁维酵母y-85菊粉酶水解菊粉的研究及其中试   总被引:1,自引:0,他引:1  
克鲁维酵母(Kluveromycessp.)Y-85在菊粉提取液培养基中生长产菊粉酶,其细胞和胞外的菊粉酶活力分别约占菊粉酶总活力的76%和24%.试验中以酶发酵液作酶液.该酶的S/I值为15.2.酶液在50,55和60℃下保温1h,活力分别残留100%,96%和65%;在8℃下放置7d,14d,酶活力分别残留98%和96%.在pH3.6~7.0内,酶活性十分稳定.5mmolL-半胱氨酸和Fe+2分别可使酶活力提高10.4%和41.2%.y-85菊粉酶水解菊粉的适宜条件是:底物为总糖浓度10%~15%菊粉提取液,pH5.0,温度为55℃,酶用量为底物每克糖加酶800u(以蔗糖为底物测酶活力)或26.3u(以菊糖为底物测酶活力)、搅拌酶解6h.在上述条件上,底物降解率最高可达98.5%.酶解液中,果糖占总还原糖量的85%.用1100L罐进行酶解中试,5批试验,底物降解率平均达94.2%.  相似文献   

4.
菊芋的酶降解及其综合利用   总被引:5,自引:0,他引:5  
菊芋富含菊粉,菊粉经菊粉酶一步酶解,可生产高果糖浆.报道了菊芋发酵生产菊粉酶、高果糖浆、酒精等研究结果,国内外研究进展以及酶解产物的综合利用.经诱变选育出的高产突变株AL154 菊粉酶的活力达146 .3 μ/mL,比出发株提高近3 倍,菊粉酶酶解菊芋提取液的最适工艺条件为:pH5 .0 ,60 ℃,底物总糖浓度10% ~20 % ,酶用量3 .0 μ/g菊糖,酶解时间10 h ,底物降解率达97 .2 % ,酶解产物中果糖占总糖的86 .1 % .  相似文献   

5.
黑曲霉产酶过程中变温操作的研究   总被引:1,自引:0,他引:1  
研究了温度对黑曲霉An-1.15生产木聚糖酶的影响,测定了正常条件下的产酶曲线。结果表明,28℃下黑曲霉An-1.15产酶最高,采用变温操作,即前24h用33℃而后用27℃培养,可在不降低酶活性的情况下缩短发酵时间16h。  相似文献   

6.
亚硫酸盐废液戊糖,己糖同步酒精发酵的调控   总被引:5,自引:0,他引:5  
休哈塔假丝酵母R(CandidashehataeR)用于亚硫酸盐制浆废液戊糖、己糖同步酒精发酵时,发酵液pH值呈规律性变化。引起pH值变化的原因是发酵过程中酸性非糖还原物被代谢及废液中存在醋酸。废液中已糖对戊糖代谢的抑制可通过调节空气量来解决。还研究了亚硫酸盐制浆废液适宜的发酵条件,在发酵初始pH5.0~5.5,温度38±1℃,溶解氧浓度0.9~1.0mg·L ̄-1的条件下对固形物为19.94%的亚硫酸盐制浆废液发酵34h,废液中戊糖、己糖能同步被酵母利用,糖的利用率为89.9%,平均每克糖产酒精0.40g,是理论得率的83.1%。  相似文献   

7.
克鲁维酵母(Kluyveromycessp.)Y-85产生并经部分纯化的胞内菊粉酶(endocelularinulinase),采用共价键交联吸附法固定化.以菊芋果聚糖为底物测定,所制得固定化酶在pH5.0和温度55℃下反应显示最大活性,对热的稳定性和贮存稳定性比游离酶明显提高,并显示出外切菊粉酶(exoinulinase)性质.在装有17.6mL固定化酶填充床反应器(packed-bedreactor)中,以1.7h-1的空间速度进料,50℃下连续操作4d,4.5%菊芋果聚糖液可被100%降解,反应器定容产率为77.0g·L-1·h-1,半衰期27d,降解产物(总糖)含85%果糖  相似文献   

8.
绿色木霉固态发酵产纤维素酶条件及酶性质的研究   总被引:4,自引:0,他引:4  
对绿色木霉 Trichoderma viride9405固态发酵产纤维素酶的条件及酶的性质进行了研究。结果表明,最适产酶条件为:秸秆粉与麸皮的比 7:3;玉米秸秆粉培养基含水量250%;花生皮粉培养基含水量150%;pH4.0~4.5;温度30℃;周期72h。在玉米秸秆粉固体培养基上,所产纤维素酶CMC活力为1386u/g,FPA活力为217u/g,棉花糖化力为325u/g。必作用的最适条件为pH4. 5~5. 0,温度 50℃;在 45℃以下, pH3. 5~6. 0之间比较稳定,室温放置半年,酶活保存率在90%以上。  相似文献   

9.
木聚糖降解菌的筛选和木聚糖酶性质的研究   总被引:15,自引:0,他引:15  
筛选两株生长快、产木聚糖酶活力高的菌种;黑曲霉(Aspergillusniger,AN01)、链霉菌(Streptomycessp.Str7B),酶活力分别达128mg/L·min和176mg/L·min;酶反应最适温度分别为60℃与50℃;最适pH值为5.0和6.0,并分别在pH2.2~5.0,5.8~6.4酶活性稳定;在60℃条件下保温1.5h,酶活力分别剩余20.5%,88.5%,其中AN01株原酶液在90℃保温10min,活力仍剩余14.5%.Cu2+对酶活表现出极强抑制,Fe2+,Mg2+,Ca2+等离子则有促进作用;用纸层析法探讨了不同培养时间各种产物产生的情况.  相似文献   

10.
嗜碱芽孢杆菌NTT33β-甘露聚糖酶的特性研究   总被引:5,自引:0,他引:5  
本文研究了嗜碱芽孢杆菌( Bacillus alkalophilic) N T T33β- 甘露聚糖酶的产生条件和酶学性质.其产酶的最佳碳源为 1% 槐豆角,最佳氮源为 1% 蛋白胨+ 0.2% 酵母膏,发酵培养36h 产酶量最高(达 61.3u/m l).甘油、葡萄糖、甘露醇等对产酶有强的阻遏作用.经分离纯化后测得纯酶的分子量为38.9 K D,等电点 p I为3.0,酶反应最适 p H 为 9.0~10.0,最适温度为80℃,稳定 p H 为6.0~9.0,稳定温度为60℃以下,金属离子中 Cu2+ , Ba2+ , M g2+ , Al3+ , Co2+ 对该酶有一定的激活作用,而 Ag+ , Hg2+ , Mn2+ 对该酶有明显抑制作用  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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