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1.
从奶粉中分离到一株同型乳酸发酵杆菌,编号TQ33,主要特点:产生芽孢,生长温度范围(20~63)℃,最适生长温度(45~50)℃,接触酶试验阳性,通气条件下生长良好,厌氧条件下发酵葡萄糖产酸不产气,主要产L(+)乳酸,菌体(G+C)为(32.45)%,生理生化性质特殊,据以上特点,将TQ33菌株鉴定为凝结芽孢杆菌(Bacilluscoagulans),LD_(50)试验表明,菌体和代谢产物属无毒物质。  相似文献   

2.
苜蓿根瘤菌AS1.159经亚硝基胍和Co ̄(60)γ射线诱变,获得一株高积累聚β-羟基丁酸(PH8)突变株J5177,积累的PHB可达细胞干重的30%,约为原出发菌株的10倍。采用分批补料发酵法,积累的PHB可达细胞干重的71%。菌体生长最适C/N比值为2.5,菌体积累PHB最适C/N比值为15;CaSO_4,Na_2MoO_4对菌体积累PHB有促进作用。  相似文献   

3.
利用常规紫外诱变技术〔1〕,处理真养产碱杆菌(Alcaligeneseutrophus)H16,采用葡萄糖为碳源的选择培养基进行筛选,获得了能高效利用葡萄糖为碳源高产聚-β-羟基丁酸(PHB)的突变菌株。摇瓶试验表明,该突变株能利用多种碳源积累PHB,PHB积累量达6.7g/L。  相似文献   

4.
经筛选得到了一株能以原油为碳源进行生长繁殖的菌株,初步鉴定为芽孢杆菌(L32),对其发酵条件进行了优化,确定出最佳的发酵条件,并确定了厌氧条件下以原油为碳源时的培养基成分。通过补加葡萄糖使其浓度保持在8g/L的方法可以提高菌体的浓度。实验结果表明,L-23可以以原油为碳源生长,并能在降低原油粘度的同时使原油培养基内水相的pH值下降。L-23能提高实验岩心的原油采收率,即在关井96h后,L-23可使原油采收率提高9.6%左右。  相似文献   

5.
耐热纤维素酶产生菌及产酶条件   总被引:10,自引:0,他引:10  
从西双版纳温泉水样中分离经鉴定为嗜热脂肪芽孢杆菌的CC22菌株(BacilusstearothermophilusstrainCC22)在60℃生长时,培养液中可积累耐热的CMCase(43mU/mL)和FPase,(106mU/mL).产酶高峰期在培养16h左右,最适起始pH为6.5,温度为60℃.CC22能利用某些无机氮形成纤维素酶,一定配比的有机氮和无机氮的混合物是CC22形成纤维素酶的最好氮源.CMCNa纤维二糖及一些农作物原料能作为碳源供CC22形成纤维素酶,高浓度葡萄糖对CC22纤维素酶的形成有抑制作用.15g/L的NaCl对CC22产酶有抑制作用,但体积分数为1%的6号微量矿质营养液无论对菌的生长和产酶均有显著促进作用.  相似文献   

6.
一株高产聚β-羟基丁酸的细菌   总被引:1,自引:1,他引:1  
从处理印染废水的活性污泥中分离出一株细胞内积累聚β-羟基丁酸(PHB)的革兰氏阴性,氧化型,可运动的短杆菌(Z_5)。经鉴定为动胶菌(zoogloea,s·p)。该菌在简单的葡萄糖蛋白胨培养基中,培养34h,积累的PHB可达细胞干重的52%(W/W)。由Z_5所得的抽提物经红外先谱,核磁共振分析确证为PHB;提取物PHB纯度可达99.87%。这是一株有工业化生产应用前景的优良菌株。  相似文献   

7.
蜂房芽孢杆菌B-91几丁质酶的合成条件   总被引:8,自引:0,他引:8  
从厦门地区牡养殖场分离筛选到一株产几丁质酶活力较高的蜂房芽孢杆菌(Bacil-lusalvei)B-91,研究了该菌几丁质酶的合成条件。结果表明:该菌在以几丁质为碳氮源的培养基中生长,能合成多量的几丁质酶。酶的合成受各种几丁质诱导。在产酶培养基中添加不同的有机或无机氮源,均能促进酶的合成,而葡萄糖、麦芽糖、蔗糖和乳糖对酶合成有阻遏作用。该菌几丁质酶合成的最适培养基初始pH为6.8,最适温度为28℃。在250ml三角瓶装50ml培养基,接种量为2%,振荡培养60h时,培养液中几丁质酶活力可达2212u/mL.  相似文献   

8.
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   

9.
用野外采回的土样进行菌种分离,得一株编号为B8的菌株,经初步鉴定该菌株是固氮菌属(AzotobacterBeijerinck)的一株固氮菌。B8菌株可利用淀粉在细胞内积累大量的聚β-羟基丁酸(PHB),从B8菌株细胞中提取出的PHB,经元素分析、核磁共振及红外光谱检测,结果与Sigma产品的性质和其纯度完全一致。经小型发酵试验测定,B8菌株产PHB的量达细胞干重的41.5%。  相似文献   

10.
产 PHB 重组大肠杆菌质粒稳定性的研究   总被引:2,自引:0,他引:2  
从工程应用的角度研究了重组E.coliHMS174(pTZ18U-PHB)的质粒稳定性,结果表明,质粒pTZ18U-PHB具有结构稳定性和分裂不稳定性,PHB在胞内的大量积累和重组菌较低的生长速率增加了质粒的分裂不稳定性。为了保证细胞的正常生长及表达,在种子培养基中必须添加氨苄青霉素(Ap);由于接种时种子带入的10mg/LAp足以杀死丢失了质粒的细胞,因而在摇瓶发酵阶段不必再添加Ap。在LB和LBG培养基中传代18次后,带质粒的菌分别为7.4%和3.5%;细胞每分裂一次,质粒的平均丢失率分别为0.96%和0.93%。并建立了野生菌的Ap敏感动力学方程和质粒丢失的动力学方程  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.
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 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   

15.
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   

16.
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   

17.
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   

18.
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   

19.
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   

20.
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   

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