晚期孕妇生殖道感染无乳链球菌与新生儿感染的相关性研究

目的探讨妊娠晚期妇女生殖道感染无乳链球菌（GBS）与新生儿感染的关系。方法在慈溪市妇幼保健院1192例胎膜早破妊娠晚期妇女进行宫颈分泌物培养,同时对其分娩的1196个新生儿进行鼻咽分泌物培养作为观察组,同时选择同期无胎膜早破的妊娠晚期妇女500例作为对照组进行比较。观察胎膜早破合并GBS阳性妊娠晚期妇女与新生儿感染的相关性。结果观察组分离无乳链球菌比例为16．1％（192／1192）,对照组分离无乳链球菌比例为6．0％（30／500）,两组比较无乳链球菌感染与胎膜早破差异有统计学意义（P〈0．05）。早破合并GBS阳性的妊娠晚期妇女新生儿感染率与破膜时间和分娩产程有关,破膜时间〈24h与〉24h的妊娠晚期妇女,其新生儿感染率与破膜时间成正比,产程〈24h的妊娠晚期妇女新生儿感染率明显低于24h以上的妊娠晚期妇女。结论妊娠晚期妇女无乳链球菌感染与胎膜早破有关,从而引起新生儿感染,为了早期预防新生儿感染,应对GBS阳性的妊娠晚期妇女及时治疗,并严格控制早破时间和缩短分娩产程。     

生物破乳菌的筛选及发酵条件的优化

生物破乳剂的开发可以降低油田乳状液对石油工业和生态环境的负面影响并减少化学破乳剂的使用量。本研究建立了一套高效、便捷的破乳菌筛选方法, 并对破乳菌的特性进行研究。利用大庆油田受石油污染土壤作为菌种来源, 将Tween 60-water(0.072%, V/V)和Span 60-oil (0.028%, V/V)以6.5:3.5体积比配置出可以稳定200 h以上的O/W型乳状液, 用于破乳菌破乳效能的评价。经过分离纯化、血平板试验、排油试验和破乳试验最终筛选出2株24 h平均排油率在80%以上的优势破乳菌, 初步鉴定为芽孢杆菌属(Bascillus)。通过该破乳菌发酵条的件优化得到, 当温度为25°C, 摇床转数为160 r/min, pH值为9, 接菌量为20%时对该破乳菌生长速率最快, 积累发酵产物的量最多; 当温度为35°C, 摇床转数为120 r/min, pH值为9, 接菌量为2%时该破乳菌代谢产物的破乳活性最高。     

生物法合成β-丙氨酸的分离纯化工艺研究

依据天冬氨酸和β-丙氨酸等电点的差异,采用静态吸附和动态吸附法,筛选适于分离β-丙氨酸的最佳树脂,并研究最佳树脂的吸附动力学和料液pH值、上样液流速,洗脱剂浓度等对β-丙氨酸分离的影响。结果表明:β-丙氨酸吸附的最佳树脂为HZ014,HZ014的静态吸附70 min达到动态平衡,吸附容量为72.92 g.kg-1,吸附率高于90%,最佳料液流速是2 ml.min-1,料液最佳pH为5.0,洗脱剂氨水浓度为4%。     

生物破乳菌形态、表面性质和物质特征研究方法与进展

生物破乳菌在石油开采与加工行业的研究已经引起各界的广泛关注,然而由于生物破乳菌菌体形态、表面性质和表面物质的复杂性,使菌体的破乳活性特征尚未被揭示。本文介绍了生物破乳剂的来源、合成及破乳机制;归纳了影响生物破乳菌破乳活性的菌体形态、表面性质和表面物质三方面因素的研究进展,特别是总结了相关研究的方法;最后在此基础上对今后研究方向提出展望。     

pH对兼性嗜碱菌Alcaligenes sp.XJ-T-1产生物破乳剂性能的影响

从受石油污染土壤中筛选出一株生物破乳剂产生菌Alcaligenes sp.XJ-T-1,生长的最适初始pH范围为9.0～11.0,为兼性嗜碱菌,能在初始pH 6.0～pH 11.0生长并产生生物破乳剂,但只有在碱性环境下才产生胞外产物。XJ-T-1菌悬液和胞外产物溶液可将蒸馏水表面张力分别降低到30 mN/m左右和35 mN/m左右。经过TLC分析,初步推测XJ-T-1产生的胞外产物为脂肽类和糖脂类的混合物。XJ-T-1菌悬液主要针对O/W型乳状液破乳,胞外产物主要针对W/O型乳状液破乳,初始pH 9.0培养下的菌悬液和胞外产物破乳效果最好。投加210 mg/L菌悬液可使O/W型乳状液在24 h的破乳率达77.5%,投加40 mg/L胞外粗产物溶液可使W/O型乳状液在24 h的破乳率达90.0%。通过透射电镜照片推测,随着培养pH提高到9.0以上,胞外产物的产生使XJ-T-1利用石蜡的过程发生变化。     

离子交换法分离D-天冬氨酸和L-丙氨酸

对离子交换法分离D-天冬氨酸和L-丙氨酸的工艺条件进行了研究。综合考虑树脂对D-天冬氨酸和L-丙氨酸的吸附容量及相对选择系数,选择了一种适合该体系分离的树脂—XH-1,并对吸附条件及洗脱条件进行了研究,确定了最佳工艺条件,为今后工业应用提供一定的依据。     

白点鲑胚胎与仔鱼发育

通过Bouin's液、5%的福尔马林、透明液固定和活体解剖观察等4种不同方法,对白点鲑(Salvelinus leucomaenis)胚胎和仔鱼发育进行了系统观察,描述了早期发育过程。白点鲑受精卵为端黄卵,沉性,橙黄色,呈圆球形。在水温3.40～8.89℃,受精卵历时1 944 h,经历6个阶段的胚胎发育破膜孵出仔鱼;初孵仔鱼全长(17.89±0.32)mm,破膜后73 d各鳍条发育完全,并出现"幼鲑斑",破膜后350d鱼体外部形态与成鱼基本相同。将白点鲑与几种鱼类进行了对比,并且探讨了其胚胎发育特点。经比较4种不同观察方法,Bouin's液固定后剥离卵膜观察是研究白点鲑等卵膜较厚鱼类的理想方法。     

耦合中空纤维膜超滤分离游离细胞催化合成ATP

对耦合中空纤维膜超滤分离进行游离细胞催化合成ATP过程进行了实验研究,考察了细胞的催化效率和膜组件的操作稳定性。结果显示,中空纤维超滤膜的耦合分离能有效地截留反应液中的游离酶,其中乙醇脱氢酶(ADH)和已糖激酶(HK)的稳态截留效率在95%以上。耦合膜分离的酵母细胞催化ATP合成反应可重复使用2.5～3.0次,酶的利用率比普通分离的细胞提高2.0～2.5倍。中空纤维超滤膜于0.1Mpa工作压力下连续11批耦合分离操作,膜的渗透性无明显下降,过滤速率保持在初速率的95%以上。在稀释速率0.25h-1下,反应体系保持了连续5h的ATP高转化率合成与分离耦合的拟稳态操作。     

pH对破乳菌Alcaligenes sp. S-XJ-1破乳性能的影响

从受石油污染的土壤中筛选出一株破乳菌Alcaligenes sp. S-XJ-1,该菌在初始pH6.0-11.0均可生长,其最适初始pH为10.0。在初始pH10.0条件下培养,破乳菌产量最高可达4.8g/L,菌悬液投加量为1000mg/L时,24h破乳率在85%以上。同时,该培养条件下得到的生物破乳菌细胞表面疏水性最大,对碳氢化合物的吸附能力达72.7%,接触角达115°。采用稳定性分析仪分别对pH7.0和pH10.0条件下培养得到的菌体的破乳效果进行分析,结果发现与初始pH7.0相比,初始pH10.0培养得到的破乳菌可以加速分散相粒径的增大,最终使乳状液破乳速率大幅提高。     

生物破乳剂产生菌混合培养及其发酵条件的优化

【目的】对菌株L1和XH1的混合发酵条件进行优化,为混合菌发酵生物破乳剂的实际生产和应用提供理论依据。【方法】利用响应面实验(RSM)的中心组合旋转设计方法(CCRD)针对混合菌的发酵条件进行优化,通过对模型乳状液进行破乳实验,以排油率作为发酵液破乳效能的评价标准。【结果】经模型的分析与验证,确定最佳发酵条件为：种子液比例(L1:XH1)为3:2,葡萄糖投加时间为第4天,投加葡萄糖后再培养21 h,液体石蜡含量3.6% (体积比)。【结论】与破乳菌XH1和L1单独培养相比,经混合培养后获得复合生物破乳剂具有投加量少、破乳接触时间短的优势。同时双株破乳菌复配培养有效地提高了培养基中主要营养物质的利用率,减少了对底物的浪费。     

Ecofriendly demulsification of water in oil emulsions by an efficient biodemulsifier producing bacterium isolated from oil contaminated environment

Objective

Water in oil emulsions increase oil processing costs and cause damage to refinery equipment which necessitates demulsification. Since chemical demulsifiers cause environmental pollution, biodemulsifiers have been paid more attention. This study aims to identify biodemulsifier-producing bacteria from petroleum contaminated environments.

Results

As a result, several biodemulsifier producing strains were found that Stenotrophomonas sp. strain HS7 (accession number: MF445088) which produced a cell associated biodemulsifier showed the highest demulsifying ratio, 98.57% for water in kerosene and 66.28% for water in crude oil emulsion after 48 h. 35 °C, pH 7, 48 h incubation and ammonium nitrate as nitrogen source were optimum conditions for biodemulsifier production. Furthermore, it was found that hydrophobic carbon sources like as liquid paraffin is not preferred as the sole carbon source while a combination of various carbon sources including liquid paraffin will increase demulsification efficiency of the biodemulsifier.

Conclusions

The appropriate potential of this biodemulsifier strengthens the possibility of its application in industries especially petroleum industry.

     

A novel high-pressure liquid-liquid extraction process for downstream processing in biotechnology: extraction of cardiac glycosides

This investigation examines phase equilibrium phenomena that can be used to create two water-like solvents for liquid-liquid extraction in downstream processing in biotechnology: a completely miscible, binary liquid mixture of water and a hydrophilic organic solvent (e. g., an alcohol) reveals a liquid phase split, when it is pressurized with a "near-critical" gas (i.e., a substance which at ambient conditions is a gas, near its critical temperature). This phase split results in two hydrophilic liquid phases. Making use of this phenomenon in process development first requires research on the phase split phenomenon and, second, research on the feasibility of biomolecule extraction and separation. In this study, basic fluid phase equilibrium phenomena are briefly described. Then, experimental results are reported for the partitioning of small amounts of cardiac glycosides (digitoxin and digoxin) on coexisting liquid phases in the high-pressure, three-phase, vapor-liquid-liquid equilibrium of the ternary system of "near critical" CO(2) + water + 1-propanol, at 313 K and 333 K. Finally, a process for extraction and separation of the aforementioned glycosides by means of the high-pressure phase equilibrium phenomenon is discussed.     

Measurement of branched chain amino acids in blood plasma by high performance liquid chromatography

A simple and rapid high performance liquid chromatographic technique is described for the separation and quantitation of plasma branched chain amino acids. After addition of a norleucine internal standard, plasma samples are acidified with acetic acid, and amino acids are separated from proteins and other plasma components by passage of the acidified plasma through an ion exchange resin. The ammonium hydroxide eluate from the resin is dried, phenylisothiocyanate derivatives are prepared, and the amino acids are separated on a Waters reverse-phase "Pico-Tag" column with an ultraviolet detector set at 254 nm. In addition to the branched chain amino acids (leucine, valine, and isoleucine), aspartate, glutamate, serine, threonine, alanine, and methionine are quantitated with high precision and accuracy, as verified by quantitative recovery and comparison with an automatic amino acid analyzer. The advantages of the method are its simplicity, speed, stability of derivatives, high reproducibility, low per-sample cost, and the use of a simple fixed-wavelength ultraviolet detector.     

Integration of Gas Enhanced Oil Recovery in Multiphase Fermentations for the Microbial Production of Fuels and Chemicals

In multiphase fermentations where the product forms a second liquid phase or where solvents are added for product extraction, turbulent conditions disperse the oil phase as droplets. Surface‐active components (SACs) present in the fermentation broth can stabilize the product droplets thus forming an emulsion. Breaking this emulsion increases process complexity and consequently the production cost. In previous works, it has been proposed to promote demulsification of oil/supernatant emulsions in an off‐line batch bubble column operating at low gas flow rate. The aim of this study is to test the performance of this recovery method integrated to a fermentation, allowing for continuous removal of the oil phase. A 500 mL bubble column is successfully integrated with a 2 L reactor during 24 h without affecting cell growth or cell viability. However, higher levels of surfactants and emulsion stability are measured in the integrated system compared to a base case, reducing its capacity for oil recovery. This is related to release of SACs due to cellular stress when circulating through the recovery column. Therefore, it is concluded that the gas bubble‐induced oil recovery method allows for oil separation and cell recycling without compromising fermentation performance; however, tuning of the column parameters considering increased levels of SACs due to cellular stress is required for improving oil recovery.     

An immobilized cell reactor with simultaneous product separation. II. Experimental reactor performance

The simultaneous separation of volatile fermentation products from product-inhibited fermentations can greatly increase the productivity of a bioreactor by reducing the product concentration in the bioreactor, as well as concentrating the product in an output stream free of cells, substrate, or other feed impurities. The Immobilized Cell Reactor-Separator (ICRS) consists of two column reactors: a cocurrent gas-liquid "enricher" followed by a countercurrent "stripper" The columns are four-phase tubular reactors consisting of (1) an inert gas phase, (2) the liquid fermentation broth, (3) the solid column internal packing, and (4) the immobilized biological catalyst or cells. The application of the ICRS to the ethanol-from-whey-lactose fermentation system has been investigated. Operation in the liquid continuous or bubble flow regime allows a high liquid holdup in the reactor and consequent long and controllable liquid residence time but results in a high gas phase pressure drop over the length of the reactor and low gas flow rates. Operation in the gas continuous regime gives high gas flow rates and low pressure drop but also results in short liquid residence time and incomplete column wetting at low liquid loading rates using conventional gas-liquid column packings. Using cells absorbed to conventional ceramic column packing (0.25-in. Intalox saddles), it was found that a good reaction could be obtained in the liquid continuous mode, but little separation, while in the gas continuous mode there was little reaction but good separation. Using cells sorbed to an absorbant matrix allowed operation in the gas continuous regime with a liquid holdup of up to 30% of the total reactor volume. Good reaction rates and product separation were obtained using this matrix. High reaction rates were obtained due to high density cell loading in the reactor. A dry cell density of up to 92 g/L reactor was obtained in the enricher. The enricher ethanol productivity ranged from 50 to 160 g/L h while the stripper productivity varied from 0 to 32 g/L h at different feed rates and concentrations. A separation efficiency of as high as 98% was obtained from the system.     

Metal biosorption-flotation. Application to cadmium removal

Biosorption, using suspended non-living biomass, and flotation (for consequent solid/liquid separation of the metal-loaded biomass) have been studied in the laboratory as a possible combined process, for the removal of toxic metals (i.e. cadmium) from dilute aqueous solutions. The various parameters of the process were investigated in depth, including re-use of biosorbent. A filter aid (contained in the biomass industrial waste used) was found not really to interfere. -potential measurements of the aforementioned system were also carried out. Promising results were obtained during continuous-flow experiments. A flotation residence time of 4 min was achieved. Metal removal and suspended biomass recovery were generally over 95%.     

生物破乳剂产生菌的筛选及其方法研究

针对生物破乳剂产生菌筛选难的问题, 采用显色法、溶血细胞测试法、表面张力测定法和排油圈法从6种不同菌源对生物破乳菌产生菌进行了筛选。通过试验筛选得到了17株生物破乳剂产生菌, 其中24h内破乳率高于70%的破乳菌有5株; 油田含油污泥、采油废水生物处理污泥和污水处理厂剩余污泥是筛选破乳菌的较好的菌源; 显色法、溶血圈法存在检测范围的局限性; 表面张力测定法和排油圈法是最为简易和准确的生物表面活性剂产生菌的筛选方法, 采用模型乳状液对生物破乳剂产生菌进行筛选最为直接和准确, 但工作量大、所需时间长, 因此在筛选高效破乳菌时, 建议采用表面张力、排油圈法进行初筛, 而后通过模型乳状液破乳进行验证。     

Effective biodemulsifier components secreted by Bacillus mojavensis XH-1 and analysis of the demulsification process

The purpose of the present study was to investigate the effective components of the demulsifying bacterial strain Bacillus mojavensis XH-1 and its demulsification process. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the shotgun LC–MS/MS method were used to separate and identify proteins with efficient demulsification activity. The zeta potential changes of the emulsion before and after addition of the biodemulsifier were tested, and the relationships between oil-in-water interfacial tension, the demulsification efficiency and the biodemulsifier structure were examined. The study results indicate that the effective biodemulsifier components were extracellular proteins attached to the cells or secreted into the culture solution that presented as a 50–80 kDa band observed by SDS-PAGE. Six of the proteins were unknown or unnamed, and the demulsifying functions of another 14 proteins had not been previously reported. The main demulsification mechanisms were determined to be solubilization and replacement. When the concentration of the biodemulsifier was low, the replacement mechanism dominated, and the demulsification ratio increased with the biodemulsifier concentration. Solubilization dominated when a high concentration of biodemulsifier was provided, and the demulsification ratio decreased as the biodemulsifier concentration increased.     

Liquid‐Crystalline Small Molecules for Nonfullerene Solar Cells with High Fill Factors and Power Conversion Efficiencies

Compared with nonfullerene‐based polymer solar cells, all‐small‐molecule solar cells normally show low power conversion efficiencies (PCEs) due to their low fill factors (FFs). Molecular stacking orientation and phase separation are the main factors affecting the performance of all‐small‐molecule solar cells. In this work, two liquid‐crystalline small‐molecule donors are designed and synthesized and a novel nonfullerene acceptor with good crystallinity developed. Owing to the face‐on orientation of the component molecules and appropriate phase separation in the active layer, a high FF of over 70% and a PCE of 10.7% are obtained from the resulting solar cells; these values are among the best obtained thus far for all‐small‐molecule solar cells. The high FF reported here is significant for a further design of high‐performance all‐small‐molecule solar cells.     

生物破乳剂产生菌的筛选及其方法研究

针对生物破乳剂产生菌筛选难的问题,采用显色法、溶血细胞测试法、表面张力测定法和排油圈法从6种不同菌源对生物破乳菌产生茵进行了筛选.通过试验筛选得到了17株生物破乳剂产生茵,其中24h内破乳率高于70%的破乳菌有5株;油田含油污泥、采油废水生物处理污泥和污水处理厂剩余污泥是筛选破乳菌的较好的菌源:显色法、溶血圈法存在检测范围的局限性;表面张力测定法和排油圈法是最为简易和准确的生物表面活性剂产生茵的筛选方法,采用模型乳状液对生物破乳剂产生菌进行筛选最为直接和准确,但工作量大、所需时间长,因此在筛选高效破乳菌时,建议采用表面张力、排油圈法进行初筛,而后通过模型乳状液破乳进行验证.