厌氧产氢菌的分离筛选、诱变选育及其产氢特性的研究

本文从四川绵竹酒厂、成都市龙泉长安垃圾填埋场以及四川大学荷花池底的厌氧污泥中先后分离得到63株厌氧产氢菌，其中H-8、H-61、HC-10等16株产氢细菌产氢能力较高，HC-10的产氢能力最高，最大产氢量和最大产氢速率分别达到2840 ml H2/L培养基和25.39 mmol H2/g drycell·h，对HC-10进行生理生化鉴定和分子生物学鉴定，判定其为clostridium sp.，对HC-10的产氢条件进行了研究，结果表明，该菌的最适生长温度为35 ℃，最适生长初始pH为7，以葡萄糖为最佳碳源，以蛋白胨为最佳氮源，不利用无机氮源，其产氢发酵液相产物以乙醇和乙酸为主，其发酵类型属于乙醇型发酵。此外，以酒糟废液作为底物，进行了菌株HC-10的生物强化试验，研究表明，投加了HC-10的强化系统其产氢量比对照高出40.32%。 同时为了获得厌氧产氢菌的高效突变株，分别以产氢菌H-8和H-61为原始菌株进行微波诱变处理，对微波诱变参数进行了优化，考察了突变株的遗传稳定性、产氢特性及耐酸性。菌株H-8经过微波诱变得到5株高产氢突变株HW7、HW33、HW181、HW184、HW195，经多次传代表明HW195是稳定的高产突变株。突变株HW195具有较好的耐酸性，在pH值为2.8时仍能生长。通过间歇发酵实验，其最大产氢量和最大产氢速率分别达到2460 mL/L培养基和27.97 mmol H2/g drycell·h，比原始菌分别提高了50.75%和41.7%。菌株H-61经过微波诱变后选育得到的突变株HW-18，其最大产氢量和最大产氢速率分别达到2190 mL/L培养基和25.86 mmol H2/g drycell·h，比原始菌分别提高了23.03%和31.00%。 为了对比各种诱变方式对产氢菌产氢能力的影响，以厌氧产氢菌H-61为原始菌株，先后经亚硝基胍(NTG)、紫外(UV)诱变，选育得到1株高产突变株HCM-23。在葡萄糖浓度为10 g/L的条件下，其产氢量为3024 mL/L培养基，比原始菌株提高了69.89%；其最大产氢速率为33.19 mmol H2/g drycell·h，比原始菌株提高了68.14%。经过多次传代实验，稳定性良好。其发酵末端产物以乙醇和乙酸为主，属于典型乙醇型发酵。其最适产氢初始pH为6.5，最适生长温度为36 ℃，以蔗糖为最佳碳源。与原始菌株相比，突变株HCM-23的产氢特性发生了改变，如生长延滞期延长，可利用无机氮源等。 From anaerobic activated sludge, 16 strains of hydrogen producing bacteria were newly isolated. One of them named as HC-10 had the highest hydrogen producing capability, under the batch fermentative hydrogen production condition, the maximal hydrogen yield and hydrogen production rate was 2840 mL/L culture and 25.39 mmol H2/g drycell·h. It was identified as clostridium sp.HC-10 by 16S rDNA sequence analysis. Various parameters for hydrogen production, including substrates, initial pH and temperature, have been studied. The optimum condition for hydrogen producing of strain HC-10 were achieved as: initial pH 7.0, temperature 35 ℃, glucose as the favorite substrate, Moreover, using distiller's solubles wastewater as substrate, HC-10 strain was added in the biohydrogen producing system to research the bioaugmentation effection. The results showed that the hydrogen production of bioaugmentation system was 40.32% higher than the noaugmentation system. An anaerobic, hydrogen producing strain H-8 was irradiated by microwave to optimize the microwave mutagenesis condition, and to test the heredity, hydrogen-producing potential and aciduric of the mutants. An aciduric mutant named as HW195 with steady hydrogen-producing capability was obtained, which can grow at pH 2.8. Its capability of hydrogen production was tested in the batch culture experiments. The maximum hydrogen yield and hydrogen production rate was 2460 mL/L culture and 29.97 mmol H2/g drycell·h, which was 50.7% and 41.7% higher than those of the initial strain, respectively. When used the strain H-61 as original strain, a mutant named as HW18 was obtained. The maximum hydrogen yield and hydrogen production rate was 2190 mL/L culture and 25.86 mmol H2/g drycell·h, which was 23.03% and 31.00% higher than those of the initial strain, respectively. The results demonstrated that microwave mutagenesis could be used in the field of hydrogen producing microorganism. The hydrogen producing strain H-61 was used as an original strain which was induced by NTG and UV for increasing and the hydrogen production capability. One of the highest efficient H2-producing mutants was named as HCM-23 with its stable hydrogen production capability. which was tested in the batch culture experiments. With the condition of 10 g/L glucose, its cumulative hydrogen yield and hydrogen production rate was 3024 mL/L culture and 33.19 mmol H2/g drycell·h, 69.89％and 68.14％ higher than that of the original strain, respectively. The terminal liquid product compositions showed that the mutant HCM-23 fermentation was ethanol type, while the original strain H-61 fermentation was butyric acid type. Varieties of parameters of hydrogen production fermentation were studied, including time, carbon source, nitrogen source, glucose concentration, glucose utilization, initial pH and incubation temperature had been studied, indicated the optimum condition of hydrogen production for the mutant HCM-23 as initial pH6.5, temperature 36 ℃, and the favorite substrate was sucrose. The hydrogen production characters of the mutant and the original strain were different, such as, the growth lag phase and the utilization of inorganic nitrogen source, etc. This work shows a good application potential of NTG-UV combined mutation in the biohydrogen production. And the hydrogen production mechanism and metabolic pathway should be explored furthermore.

Energy momentum for randall sundrum models

We investigate the conservation law of energy momentum for Randall-Sundrum models by the general displacement transform. The energy momentum current has a superpotential and are therefore identically conserved. It is shown that for Randall-Sundrum solution, the momentum vanishes and most of the bulk energy is localized near the Planck brane. The energy density is epsilon = epsilon(0)e(-3 vertical bar y vertical bar).

Largely deformed dinuclear system formed in F-19+Al-27 dissipative collision

Excitation functions are measured for different charge products of the F-19+(27) Al reaction in the laboratory energy range 110.25-118.75MeV in steps of 250keV at theta(lab) = 57 degrees, 31 degrees and -29 degrees. The coherence rotation angular velocities of the intermediate dinuclear systems formed in the reaction are extracted from the cross section energy autocorrelation functions. Compared the angular velocity extracted from the experimental data with the ones deduced from the sticking limit, it is indicated that a larger deformation of the intermediate dinuclear system exists.

Average property of isospin effects induced by neutron-halo nuclei

We study the average property of the isospin effects of reaction mechanism induced by neutron-halo nuclei within the isospin-dependent quantum molecular dynamics model. We find that the extended neutron density distribution for the neutron-halo projectile brings an important isospin effect into the reaction mechanism, which induces the decrease of nuclear stopping R; however, it induces the obvious increases of the neutron-proton ratio of nucleon emissions (n/p)(nucl) for all of the beam energies in this work, compared to the same mass stable colliding system.

稠油降解菌的筛选及其对胶质和沥青质生物降解

以稠油为唯一碳源,从辽河油田石油污染土壤、渣油中,经富集培养,分离筛选出细菌菌株11株、真菌23株和放线菌10株。将在含油培养基上长势良好的菌株进行室内摇瓶实验,发现真菌的降解效果好于细菌,F2006的降解效果最好,14d去除率达到39.8%。在胶质和沥青质污染土壤中,观察真菌F4、F2008、F9902、F2006、F2017、F6和F9904在14d、28d和42d对胶质和沥青质的去除率,测试结果表明,菌株F2006和F2008降解效果较好,在42d时去除率分别达到55.73%和57.62%。两次实验说明,菌株F2006为降解胶质和沥青质的优势菌株,在生物修复中具有较好的应用前景。

土壤和水稻中正十六烷的结合残留

利用14C-正十六烷示踪技术、水稻盆栽和溶剂连续化学提取方法，研究了正十六烷在土壤水稻系统中的某些行为。结果表明，正十六烷容易进入水稻并累积于籽实，对人类健康产生不良影响。实验还探讨了土壤和水稻体内14C－正十六烷的存在和代谢转化过程。土壤中的正十六烷14C主要以溶剂可提取形式存在，大约占总14C的39％，其次是存在于土壤未分解的植物残体（大约占25％）和富啡酸组分（大约占23％）。以无机碳酸盐存在的大约占10％，进入胡敏酸（包括胡敏素）结构的数量较少，总计约占3％。正十六烷在水稻体内主要以结合残留态存在，大约占植物体总14C的98％，石油醚、乙醇和乙醇等有机溶剂可提取部分大约占2％。正十六烷进入水稻系统后，经历时间愈短，结合残留态愈少，溶剂可提态愈多。在石油醚提取液中，Rf值大于正十六烷的极性代谢物占21％。

A discrete square global grid system based on the parallels plane projection

Knowledge Innovation Project of Chinese Academy of Sciences [KZCX3-SW-347]; National Science Fund for Distinguished Young Scholar [40225004]

A discrete square global grid system based on the parallels plane projection

We developed a direct partitioning method to construct a seamless discrete global grid system (DGGS) with any resolution based on a two-dimensional projected plane and the earth ellipsoid. This DGGS is composed of congruent square grids over the projected plane and irregular ellipsoidal quadrilaterals on the ellipsoidal surface. A new equal area projection named the parallels plane (PP) projection derived from the expansion of the central meridian and parallels has been employed to perform the transformation between the planar squares and the corresponding ellipsoidal grids. The horizontal sides of the grids are parts of the parallel circles and the vertical sides are complex ellipsoidal curves, which can be obtained by the inverse expression of the PP projection. The partition strategies, transformation equations, geometric characteristics and distortions for this DGGS have been discussed. Our analysis proves that the DGGS is area-preserving while length distortions only occur on the vertical sides off the central meridian. Angular and length distortions positively correlate to the increase in latitudes and the spanning of longitudes away from a chosen central meridian. This direct partition only generates a small number of broken grids that can be treated individually.

Effects of rare earth on the structure and properties of Mg–6Zn–5Al–4Gd–1RE (RE = Ce or Y) alloys

The microstructures and mechanical properties of Mg-6Zn-5Al-4Gd-1RE (RE = Ce or Y) alloys were investigated. The addition of Ce or Y obviously refines the grain size for the Mg-6Zn-5Al-4Gd-based alloy, while the Y element has a better refining effect. The Ce and Y show different grain-refining mechanisms: Ce addition mostly promotes the growth of secondary dendrite, while Y addition mainly increases the heterogeneous nucleation sites.

Arabinogalactan as a carrier for contrast agent in magnetic resonance imaging

Arabinogalactan-Gd-DTPA was synthesized by the reaction of diethylenetriaminepenta-acetic acid (DTPA) bisanhydride with polysaccharide in dry DMSO and characterized by FTIR, elemental analysis and ICP-AES. Its stability was investigated by competition with Ca2+, EDTA, DTPA. The t(1)-relaxivity is 8.06 mmol(-1) . L . s(-1) in D2O, 8.48 mmol(-1) . L . s(-1) in 0.725 mmol . L-1 BSA, respectively. t(1)-weighted MR imaging of rat kidney and liver showed a remarkable enhancement post injection of Arabinogalactan-Gd-DTPA. The results indicate that the arabinogalactan-Gd-DTPA is a potential contrast agent for MRI.

以阿拉伯半乳聚糖为载体的磁共振成像造影剂的研究

合成了阿拉伯半乳聚糖修饰的 DTPA钆配合物 ,用红外光谱、元素分析、 ICP-AES等手段进行了表征 ,用竞争性方法研究了其在水溶液中的稳定性 ,测试了其在水中及 BSA溶液中的弛豫性能 ,并进行了体内成像实验 .结果表明 ,其弛豫效率是目前临床所用造影剂 Gd-DTPA的 1 .5～ 2 .0倍 ,对肝脏和肾脏 MRI信号具有良好的增强效果 ,是比较好的潜在磁共振成像造影剂

四卤合金属酸十六铵的光电子能谱研究

用 AIKα(hυ=1486.6 eV)X-射线测量 15种四卤合金属酸十六铵的光电子能谱.讨论了这些化合物的Zn(2p)、Co(2p)、Cu(2p)、Mn(2p)、Cd(3d)、Cl(2p)、Br(3d)、I(3d)、N(1s)的芯能级结合能的化学位移.根据Pauling电负性讨论了这些数据和计算电荷的关系.讨论了配位体X(Cl,Br,I)、中心离子M(Zn,Co,Cu,Mn,Cd)和质子化十六胺(C16H33NH3)+的关系.

红藻无性繁殖系的诱导及其发育机制的初步研

以红藻中的角叉菜（Chondrus ocellatus）、龙须菜（Gracilaria lemaneiformis）、真江蓠(Gracilaria asiatica)和海膜（Halymenia sinensis）为材料，观察了红藻幼苗的早期发育，通过组织培养构建无性繁殖系，并初步探讨了红藻无性繁殖系的发育及分化机理，为海藻无性繁殖系的获得提供理论基础和依据。 在室内进行了角叉菜的四分孢子和果孢子的细胞培养，并观察其早期发育过程。结果表明，四分孢子和果孢子的早期发育是相似的，可主要分为三个阶段：早期分裂阶段、盘状体阶段和直立体形成阶段。 切段组织培养表明，红藻无性繁殖系的获得主要通过两种途径：一种为切段组织经过培养可直接形成再生植株；另一种为切段组织经培养脱分化，诱导出愈伤组织或类愈伤组织，愈伤组织或类愈伤组织再分化，形成盘状体，盘状体继续发育即可形成再生植株。 通过切段组织培养，获得了龙须菜和真江蓠再生植株。在PES培养液中，添加6－BA（0.25 mg/L）对龙须菜切段组织再生新枝的诱导有促进作用，诱导率可高达84.4％，高浓度的IAA或6－BA（4 mg/L）对切段组织有损伤作用。实验证明伤口大小对切段组织再生新枝有影响，且伤口太大对再生新枝的形成不利。龙须菜的切段组织培养过程中表现出极性。 通过组织培养，诱导出海膜类愈伤组织—丝状体。添加植物生长调节类物质（IAA 和 6-BA）对海膜丝状体的诱导无促进作用。海膜切片在消毒海水中培养即可获得丝状体。海膜丝状体的外植体来源主要有两个：一是健康的藻体； 另一是盘状体，其丝状体的诱导率分别为80％ 和90％。筛选出了丝状体适宜的生长条件：13－23℃，10－15 μE•m−2• s−1，12h：12h（Light: Dark），其中18℃为最佳生长温度。高的光照强度（50 μE•m−2•s−1）对丝状体产生损伤作用。 红藻无性繁殖系的发育途径，根据其获得途径也有两种情况。经过切段组织培养直接获得的无性繁殖系，是切段切口处已分化的细胞表现其全能性，恢复分裂能力，再生新枝，切段表现出极性。极性的上端产生新枝，下端形成固着器，成为一个完整的植株。经过愈伤组织和类愈伤组织获得的无性繁殖系，是切口处已分化的细胞表现其全能性，经脱分化形成愈伤组织和类愈伤组织，附着在基质上后，再分化形成盘状体，按照孢子的早期发育途径，形成直立体幼苗。 通过SDS-聚丙烯酰胺凝胶电泳分析，对龙须菜正常藻体及无性繁殖系发育过程中蛋白的表达进行检测，检测出表达差异的蛋白质，推测这两个蛋白可能与龙须菜切段组织再生有关，其中30 KD的蛋白仅在再生新枝中表达，150 KD和125 KD的蛋白仅在正常生长的龙须菜和龙须菜切段的极性下端中表达。 根据高等植物中与萌芽、分生组织以及愈伤组织发育相关的基因序列保守区设计了五对特异引物，通过PCR和RT-PCR扩增检测及DNA测序分析，对红藻无性繁殖系早期发育相关的基因序列，进行了初步分析。