Galactomyces reessii转化β-甲基丁酸生产β-羟基-β-甲基丁酸

Galactomycesreessii可将 β-甲基丁酸 ( MBA)转化为 β-羟基 - β-甲基丁酸 ( HMB)。摇瓶实验表明发酵过程中提供生长因子的酵母萃取物浓度以 3 g/L较适宜。高浓度钠、铵离子对菌体生长有抑制作用 ,为保证转化 MBA所需 p H可采用混合碱 ( Na OH、KOH、NH4 OH)来调节 ,以防止单一阳离子浓度过高对菌体生长和产物形成的抑制。MBA对菌体生长有明显的抑制作用 ,1 0 g/L的MBA可使菌体浓度减少 3 0 %。分批补料发酵中 ,连续流加葡萄糖和 MBA,控制发酵液中葡萄糖浓度不超过 3 g/L,MBA浓度不超过 4g/L ,1 0 2 h时 HMB浓度达 2 9.0 g/L ,转化率达 5 7.3 % ,HMB平均生产率达 0 .0 98g/( L· h)。     

强化工业大肠杆菌生长特性的研究

大肠杆菌是制药工业中的重要蛋白质药物生产菌株。然而乙酸积累、中心碳代谢负担过重等不良因素严重制约着大肠杆菌的高密度生长。利用Red同源重组技术,构建icd和ptsG双基因敲除大肠杆菌菌株,以分流碳代谢流,提高碳利用效率,最终增加菌体生物量。同时构建ppc过表达质粒,减少乙酸积累。发酵结果显示,构建的重组菌株产酸量大幅减少,pH值平均升高20%,菌体浓度增加了50%,生长特性得到了强化。     

耐氨光合细菌RHODOBACTER SPHAEROIDES G2B处理有机废水产氢性能研究

开发以有机物水解产物丁酸、乙酸、丙酸与乙醇作为供氢体的产氢光合细菌体系具有十分重要的作用.本文研究了耐氨光合细菌Rhodobacter sphaeroides G2B利用这些有机酸产氢其它一些影响产氢的因素.结果显示就产氢效率而言,以基质为有机酸+牛肉膏具有较高的产氢能力;基质为有机酸+谷氨酸时,菌体生长最佳.产氢活性随光照强度的增加而提高,在8000Lx光照条件下其最大产氢速率达到15.3ml·h-1·g-1细胞干重.中性初始pH(6.8-7.5),产氢效率很差,pH值在5.0以下,具有高的产氢效率.氨氮抑制结果显示,高达35mg/L的氨氮对Rhodobacter sphaeroides G2B产氢没有明显影响,但当浓度达到60mg/L将对产氢产生较明显的抑制作用.     

不同阳极电势驯化对于Clostridium butyricum 葡萄糖代谢影响研究

新筛选出的Clostridium butyricum 作为研究菌株,研究其在不同阳极电势驯化期内葡萄糖代谢与电化学活性的差异。使用1mM葡萄糖为底物连接1000 Ω外电阻时,电池的输出电压约为0.09 V。该电池性能显示出C.butyricum 具有良好的电活性。在控制阳极电势（＋0.6, ＋0.2 和 －0.2 V,vs Ag/AgCl）驯化菌株的过程中,C.butyricum电活性及其葡萄糖代谢显示出明显的不同。在驯化后期,0.6 V和0.2 V组的最大输出电流分别为1.8和1.2 mA,而-0.2 V组只有0.02 mA。但是表征游离菌体的OD600的结果显示-0.2 V组具有大量游离菌体。这意味着高阳极电势驯化出的生物膜具有高电活性。不同组别在驯化末期葡萄糖代谢也出现了不同。乳酸,丁二酸和乙醇的含量随着生物膜电活性的增高而减少,同时乙酸和丁酸的含量却上升。但是-0.2 V组生成了大量丁酸（345 mg/L）,同时却只有少量二氧化碳生成（4 %）。实验结果表明高阳极电势促进生物膜的电极呼吸代谢同时抑制其发酵代谢从而表现出高生物电活性。本文拓展了电活性微生物在发酵条件下产电过程的理解。     

丁酸甲烷发酵优势菌群的选育及其丁酸降解特性

选育以产氢产乙酸菌为优势的复合菌群,对于开发基于强化产氢产乙酸菌群功能作用的高效厌氧生物处理技术具有重要意义。研究表明,以厌氧折流板反应器中的厌氧活性污泥为出发菌群,通过丁酸盐培养基的定向培育,可选育到以降解丁酸的产氢产乙酸菌和产甲烷菌为优势的复合菌群。该菌群在初始pH 7.0、初始丁酸浓度9 319 mg/L和35℃等条件下,经过27 d的培养,其丁酸降解率达到95%,平均降解速率为39.2 mg/d,累积产气量为290 mL,丁酸的比产气速率达到3.95 mL/g,发酵气中的CH_4含量为61%,CO_2含量为22%。     

微生物电解乙酸合成高值有机物

以微生物电解池为平台, 考察了阴极电势, pH以及初始乙酸盐浓度对乙酸还原及其丁酸、乙醇等产物积累的影响.结果显示, 恒定阴极电势-900mV(vs.Ag/AgCl)、 pH60时, 初始乙酸钠浓度为10g/L时, 丁酸产量最高, 可达到80(±5)mg/L, 乙醇积累26(±5)mg/L.在-900mV阴极电势下, 总碳回收率达到632%, 产物电子回收率为1306%; 在-800mV阴极电势下, 总碳回收率达到428%, 产物电子回收率为544%.控制阴极电势-850mV, 初始乙酸钠浓度由1g/L增加到5g/L, 丁酸的产量由488mg/L增加到762mg/L, 提高了56%.扫描电镜显示, 阴极碳毡上菌体主要为杆菌.对阴极附着微生物进行变性梯度凝胶电泳(PCR DGGE)分析发现, 假单胞菌属(Pseudomonas)和梭菌属(Clostridium)为主要的功能菌群, 假单胞菌可能与阴极电子传递有关, 而梭菌可能与高值有机物的合成有关.     

光合菌群利用丁酸产氢的初步研究

对影响光合茵群利用丁酸产氢的主要因子:初始细胞浓度、温度、初始pH值、光照强度和丁酸浓度进行了研究.结果表明,光合茵群在初始细胞浓度0.2～O.3 g/L,温度30~40℃,PH 6.0～9.0,光照强度2000～8000 Lx,丁酸浓度6～30 mmol/L的范围内均可以保持较高的产氢效率.当初始细胞浓度为0.3 g/L、温度30℃、初始PH 7.0、光照强度为4000 Lx、丁酸浓度为30 mmol/L时该光合茵群具有最大产氢量364 mL,最大产氢效率5.4 mol-H_2/mol-丁酸和最大产氢速率22.2 mL/L/h.     

厌气反应器对基质扰乱的响应

5套 37℃的扰乱试验实施在 3台厌气完全混合反应器中。三反应器分别处理着以丙酸、丁酸和混合脂肪酸为基质的废水。扰乱由脉冲添加丙酸、丁酸或甲酸来建立。结果表示 ,扰乱立即导致了相应的酸和氢分压(pH2 )的浓度积累。但所有反应器能完全地恢复在 2 0 0h之内。混合液相中丙酸和丁酸的积累没有导致pH的重大变化。但是 ,PH2 的增加限制了丙酸和丁酸的转换 ;各自的阈值分别为 2 1× 10 - 4及 1 1× 10 - 3atm。异丁酸和二高分子羟基酸 ,valerate和caproate ,被检出存在于一些被扰乱的反应器流出水中。对于丁酸异构化pH2 的作用是非决定性的。实验数据的热力学分析表示 ,valerate和caproate的形成或归结于pH2 的增加或独立于pH2 的增加。在后者 ,形成直接地归结于混合液相中丙酸或丁酸的浓度增加。     

丁酸梭菌LMG1213、A69及巴氏梭菌LMG3285~T在不同碳源上生长产氢的研究

丁酸梭菌和巴氏梭菌是两种产氢能力很强的细菌。本文研究了Clostridium butyricum LMG1213、A69及Clostridium pasteurianum LMG3285~T在不同碳源上的生长及产氢。不同的菌株对碳源的利用差异很大,但葡萄糖做碳源时都能很好的生长产氢。     

ASBR中加载活性炭对葡萄糖厌氧发酵产氢的影响

在初始pH值为6.0、温度为60℃、水力停留时间(HRT)分别为48,24,16,12h条件下研究了粗、细活性炭载体的添加对厌氧序批式反应器(ASBR)利用葡萄糖厌氧发酵产氢的影响.结果表明添加活性炭载体能使ASBR系统运行更加稳定(出水pH值和氢气产量波动较小),提高氢气产率(葡萄糖产生的氢气的物质的量)和产氢速率(反应器单位有效体积产生的氢气体积).HRT为48,24,16,12h时细活性炭生物载体的添加使得ASBR反应器氢气产率分别提高65%,63%,54%,56%.HRT为12h时添加细活性炭的ASBR产氢速率达到最大,为(7.09±0.31)L.(L.d)-1,相应的氢气产率为(1.42±0.03)mol.mol-1.主要代谢产物为乙醇、乙酸、丙酸和正丁酸,其中乙酸和正丁酸占出水溶解性代谢产物的质量分数分别高达30%～34%和46%～66%,是典型的丁酸型发酵,加载活性炭可以提高ASBR反应器出水溶解性代谢产物质量浓度.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.