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1.
棒曲霉UA—2木聚糖酶的蔗渣固态发酵   总被引:3,自引:0,他引:3  
棒曲霉(Aspergilusclavatus)UA-2固态发酵蔗渣产木聚酶的培养基为每克蔗渣加营养液5ml,初始pH8.5.营养液的适宜组成为每升含:NH4NO310g、K2HPO46g、MgSO4·7H2O0.75g、CaCl20.75g、FeSO4·7H2O11.25mg、MnSO4·H2O3.75mg、ZnSO43.0mg、CoCl24.5mg.在上述培养基中接入其湿重10%(W/W)的新鲜的UA-2种子曲,28℃培养108h,其木聚糖酶,滤纸降解酶和羧甲基纤维素酶的活力分别为2695.6、28.5和42.7u/g蔗渣.酶反应的最适pH5.0,最适温度50℃;在pH4.0~11.0内酶活性十分稳定.50℃保温1h,酶活剩余55%,8℃下放置23d,活力几乎不变.磷酸盐,半胱氨酸对酶有激活作用,EDTA和对氯汞本甲酸对酶有抑制作用  相似文献   

2.
以四种抗旱性不同的水、旱稻幼苗的茎、叶为实验材料,应用DNS法测定β-淀粉酶的活性,比较抗旱性不同品种间β-淀粉酶酶学性质(包括酶的最适温度、热稳定性、抑制剂和激动剂对酶活性的影响以及Km值)的差别.结果表明,所有供试品种β-淀粉酶的最适温度为40℃;不抗旱的83-8和82-1β-淀粉酶的热稳定性强于抗旱的秦爱和78-8-10;EDTA和Cu2+,Zn2+,Mg2+,Pb2+和Hg2+等金属离子是β-淀粉酶的抑制剂,Mn2+,Ba2+,Co2+和Ca2+等金属离子β-淀粉酶的激动剂;旱稻品种β-淀粉酶的Km值大于水稻.  相似文献   

3.
本文研究了枯草杆菌AS1.398发酵培养制备中性蛋白酶,对发酵培养基配比,培养条件,金属离子的影响等进行了摇瓶试验。制备的AS1.398中性蛋白酶有如下性质:最适PH7.2-7.4,在PH6.5-8.0稳定。最适温度42-44℃,35℃下处理2小时能保持约85%酶活力,60℃下10分钟酶完全失活,此酶被EDTA和Cu2+所抑制  相似文献   

4.
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   

5.
背角无齿蚌酸性磷酸酶的分离、纯化及部分性质研究   总被引:6,自引:0,他引:6  
从背角无齿蚌外套膜中,经盐析,DEAE-Sephadex A-50离子交换柱层析及Sephadex,G-150凝胶过滤等步骤,分离提纯到一种酸性磷酸酶,提纯倍数88.25酶液比活力为24.7U/mg,通过动力学方法测得其最适pH值为4.8,最适温度为50℃,同样以对硝基苯磷酸二钠作底物测得其Km值为0.73mmol/L ,Zn^2+对酶有激活作用,而F^-,Pb^2+和Ba^2+则对酶有一定的抑制  相似文献   

6.
黑曲霉单宁酶的纯化及部分性质研究   总被引:7,自引:0,他引:7  
黑曲霉在五倍子单宁的诱导下产生单宁酶。通过(NH4)2SO4分形沉淀,DEAE-Sepharose离子交换层析,Sephadex G-150凝胶过滤,从黑曲霉的发酵液和菌丝中纯化得到凝胶电泳均一的单宁酶。酶作用的最适温度为30℃,最适pH值为5.5,在温度10-30℃和pH4-6之间保持稳定,金属离子对单宁酶没有的激活作用,Fe^2+和Mn^2+则对酶有抑制作用。  相似文献   

7.
南欧紫荆萌发种子的提取液,经硫酸铵分级沉淀,DEAE-纤维素柱层析,Bio-Gel P-60和Sephadex G-100柱层析,得到了酶活为98.6μ/mg的甘露聚糖酶。柱层析和聚丙烯酰胺凝胶电泳均表明其为均一性物质。南欧紫荆甘露聚糖酶由两个分子量为2万的相同亚基组成,可将以甘露聚糖为主链的多种半纤维素水解为含4 ̄6个单糖残基的寡糖片断。它的最适pH为5,最适温度为37℃。Zn^2+对该酶活性有  相似文献   

8.
木霉4131菌株纤维素酶的分离纯化和部分性质研究   总被引:6,自引:0,他引:6  
绿色木霉(Trichoderma Viride)突变菌株4131^[1]产生的纤维素酶经过sephadexG-75和DEAE-sephadex-A-25两种层析分离,分离得到具有内切α-葡聚糖酶(CMCase)活性的纯组分,提纯后酶的比活力提高到原来的26.2倍;回收率为32.8%,分子量为56900,等电点为4.0,最适反应温度为55℃,最适pH为4.5,金属离子K^+,Na^+,Mg^2+对其  相似文献   

9.
福寿螺β-葡萄糖苷酶的分离纯化及性质的初步研究   总被引:12,自引:5,他引:7  
以福寿螺内脏为材料,经本实验室开发的工业生产法制备粗酶粉,进一步采用葡聚糖凝胶(SephadexG-200)和DEAE-SephadexA-50柱层析纯化,获得经SDS-聚丙烯酰胺凝胶电泳鉴定为单一纯的β-葡萄糖苷酶制剂.测定该酶的最适反应温度为43℃,最适反应pH为5.1;在pH5.1,45℃下,该酶催化水杨素水解的Km值为3.40mmol/L,活化能为50.63kJ/mol.研究几种效应物对酶活力的影响,结果表明:Mn2+、Co2+对酶有激活作用,而Cu2+、Hg2+、Pb2+、SDS及脲对酶有不同程度的抑制作用,其中Cu2+和Hg2+对该酶的抑制作用最强,其抑制机理均表现为非竞争性抑制  相似文献   

10.
本文对绿色乳杆菌(L.Viridescens)B175产生的α-羟基戊二酸脱氢酶用硫酸铵盐析;DEAE—纤维素柱层折;超滤浓缩;苯基琼脂糖凝胶(PhenylSepharose)疏水层析等方法纯化,使酶的纯度提高117倍。通过HPLC和等电聚焦测得该酶的分子量约为66,000,等电点为4.2。酶催化作用的最适pH5.5,最适温度为60℃,对α—酮戊二酸和NADH的Km值分别为0.14×10(-3)M和0.03×10(-3)M。  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.
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   

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.
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   

15.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
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   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
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   

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