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1.
干酪素水解产物的膜分离   总被引:1,自引:0,他引:1  
以干酪素酶解产物为介质对膜分离进行了研究。讨论了碱性和中性条件下膜分离过程中膜两侧浓度、流通量(J)和总氮截留率(σ)的变化。发现pH值低法染度高,截留分子量大的膜污染度大。用0.1mol/L的氢氧化钠和5mL/L的84消毒液浸泡洗涤可使膜的水通量恢复94%。在干酪素水解的超滤中,阻力主要来自于凝胶层。凝胶层的阻力大1至2个数量级。  相似文献   

2.
陈坚 《甘肃科技纵横》2003,32(6):47-48,53
膜分离技术在生物制药生产中已大规模应用。膜分离技术常被用于分离、浓缩、分级与纯化生物产品.根据目标产品不同,选用的膜及分离技术组合也有所不同.本文对膜分离技术在生物制药中的实际应用做一浅谈。  相似文献   

3.
利用扇贝边制造水解动物蛋白的研究   总被引:1,自引:0,他引:1  
选用复合蛋白酶酶解扇贝边制备水解液,并优化酶解工艺条件;采用中空纤维超滤膜对水解液进行分离纯化,制造高质量的水解动物蛋白,并测试膜分离试验操作条件对分离效率的影响.研究结果表明,先用枯草杆菌蛋白酶酶解4h,然后用风味蛋白酶继续酶解,可以显著提高酶解液中多肽、短肽及游离氨基酸的含量;超过滤的操作压力、温度、酶解液的pH值及浓缩比等因素都将影响超过滤效率,在操作压力不高于0.10MPa,pH值为7.0~7.5,温度为43℃,每过滤10min后就对超过滤膜进行2min的反冲洗等操作条件下,可以大大提高超过滤的分离效率、减少膜的污染及延长膜的使用寿命;试验结果还表明,超过滤分离后水解液的感官指标明显优于未分离的水解原液。  相似文献   

4.
考察了PEBA2533渗透汽化膜分离稀水溶液中邻甲酚的性能,并运用渗透汽化-分级冷凝工艺回收高纯度邻甲酚晶体。采用扫描电子显微镜对PEBA2533膜的表面及断面进行表征,通过膜的溶胀实验考察了PEBA2533膜对邻甲酚的吸附性能,考察了在不同原料质量浓度及原料液温度时PEBA2533膜对邻甲酚的分离性能。结果表明:随着原料液浓度增大,邻甲酚的通量不断增大;在原料液质量浓度范围2 000~7 000mg/L内,分离因子处于较高的范围(59~105).随着原料液温度升高,邻甲酚与水的通量均明显增大,同时分离因子也逐渐增大;当原料液质量浓度与温度为7 000mg/L,70℃时,邻甲酚晶体通量高达295.9g/(m~2·h),纯度为99.9%.  相似文献   

5.
以大豆蛋白为原料,利用微波加热和碱性蛋白酶、胰蛋白酶和中性蛋白酶水解大豆蛋白,制备单酶、双酶、三酶联合水解的大豆多肽,用葡聚糖G-50排阻色谱法进行分离检测,确定各级分的分子量分布范围.凝胶层析分析结果表明,三酶联合水解得到的大豆肽相对分子质量分布主要在1 100 u以下,而双酶联合水解则在2 000 u以下,可见三酶联合水解效果优于双酶,更优于单酶.此外,物化特性研究表明,蛋白酶水解使得大豆蛋白溶解性、起泡性及起泡稳定性等大大改变.大豆多肽具有良好的溶解性,在蛋白质的等电点附近,不受pH值的影响,且具有高浓度、低粘度的特点,以及良好的吸湿性、保湿性和热稳定性和强起泡能力.  相似文献   

6.
通过研究鲍鱼水解肽的清除自由基能力、还原能力来评价其抗氧化活性,测定水解肽的相对分子质量分布情况、氨基酸含量,对鲍鱼水解肽的营养价值进行全面分析. 结果表明:鲍鱼水解肽具有较强清除自由基的能力和还原力;其相对分子质量在107~10031u范围内呈连续分布,其中小于5000u的水解肽占比达82.0%;水解肽由18种氨基酸组成. 当温度在20~60℃,pH值为7、8、10时水解肽的活性无显著变化,金属离子对DPPH自由基的影响随质量浓度增加逐渐增强,经胃蛋白酶和胰蛋白酶消化5h后,DPPH自由基清除能力保持率分别为(66.03±0.29)%、(109.03±0.57)%.  相似文献   

7.
谷氨酰胺转移酶对食物蛋白质成膜性能的影响   总被引:1,自引:1,他引:1  
研究了添加谷氨酰胺转移酶(TGase)对大豆分离蛋白(SPI)、酪蛋白酸(NaCN)、明胶、乳清蛋白浓缩物(WPC)、小麦面筋蛋白(WG)及花生分离蛋白(PPI)6种蛋白质成膜特性的影响.研究结果表明:在成膜溶液中加入TGase,蛋白质膜的抗拉强度和表面疏水性有不同程度的改善,其中WG,SPI,NaCN和明胶这4种蛋白质膜的抗拉强度分别增加36.2%,17.7%,13.1%和25.6%(P≤0.05);NaCN,SPI,WPC,WG和明胶这5种蛋白质膜的表面疏水性分别增加216.1%,116.9%,30.5%,26.4%和2.4%(P≤0.05);同时膜的水分含量、总可溶性物质量及透光率也明显降低;明胶膜、NaCN膜和WPC膜的断裂伸长率分别增加16.3%,72.6%和172.3%,SPI膜和WG膜的断裂伸长率则分别降低7.5%和36.2%.电泳分析表明TGase使6种蛋白质均产生了共价交联.  相似文献   

8.
膜生物反应器处理餐饮废水的初步研究   总被引:7,自引:0,他引:7  
通过对膜生物反应器处理餐饮废水的研究,分别考察了膜组件的操作压力,膜面流速以及活性污泥浓度等对膜通量的影响.结果表明,膜组件的操作条件为:P=0.2MPa,V=6.5m/s-7.5m/s时较为合适;压力比较低时,膜通量与压力成正比,压力比较高时,膜通量与压力无关.随温度的升高,膜通量成比例的增加.膜通量与污泥浓度呈线性关系.膜面流速并非越高越好.采用SEM对膜污染情况进行了分析.并对膜清洗方法进行了研究.本实验确定膜的清洗条件为:清水冲+0.2%Na10(浸泡0.5h)+1%醋酸(浸泡0.5h),清水反冲可使膜通透能力略有恢复,NaC10浸泡后可使无机膜通透能力恢复到原来的62%,酸洗后可使无机膜通透能力恢复到原来的84%以上.  相似文献   

9.
超声波在酶法生产紫菜降血压肽过程中的应用   总被引:7,自引:0,他引:7  
为从紫菜蛋白中制备降血压肽,采用8种商业蛋白酶进行筛选,确定了以中性蛋白酶作为水解用酶和相应的酶解条件.研究了超声波处理紫菜蛋白后对酶解过程的影响,超声波处理后紫菜蛋白水溶液中游离氨基酸、酸溶性肽的质量浓度未变化,紫菜蛋白的紫外可见差示光谱也未出现变化;超声波处理的紫菜蛋白经酶解的产物,与未超声处理紫菜蛋白在同样条件酶解的产物相比,水解度增加1.1倍,IC50值降低29.5%.结果表明,超声处理没有破坏紫菜蛋白的分子结构,可能使它的分子空间构象发生变化,更加容易与酶分子结合,促进了酶解的进程.  相似文献   

10.
自生生物动态膜反应器处理市政污水的特性   总被引:6,自引:0,他引:6       下载免费PDF全文
实验采用0.1mm孔径的筛网自制膜组件制备自生生物动态膜反应器,考察了自生生物动态膜的形成和再生,膜孔径、膜通量和污泥浓度对自生生物动态膜形成的影响,以及对模拟城市污水的处理效果.实验结果表明,自生生物动态膜可在48h左右形成,其中滤饼层在10min左右即可形成,自生生物动态膜的再生可在50min左右完成.在HRT为4h.,膜通量为20,8Lm^-1h^-1,MLSS为4000mg/L左右时,系统稳定运行40d里,出水水头压差保持在9mm左右,出水的SS未检出,浊度均小于5NTU,氨氮的去除率保持在80%以上,COD平均去除率为87.5%,膜分离对有机物的平均去除率为18.6%.  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.
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   

15.
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   

16.
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   

17.
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   

18.
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   

19.
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   

20.
赵英华 《科技信息》2008,(12):219-220
0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation's behavior in their social life throughout the long history is beyond list.  相似文献   

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