一株耐温耐盐烃降解菌Geobacillus sp. XDF-4性能

从大庆油田龙虎泡区块采油地层水中分离得到一株性能很好的耐盐耐温的兼性烃降解菌XDF-4,经形态观察、生理生化实验和16S rDNA基因序列分析,初步鉴定为地芽孢杆菌Geobacillus sp..该菌在45～75℃、pH 6.5～9.0、盐的质量分数0～10%下生长良好,其最适生长温度为65℃,最适盐的质量分数为 3.0%.研究发现,该菌株能以原油为唯一碳源生长并合成生物表面活性剂, 发酵7 d, 其发酵液表面张力从68.59 mN·m-1降到29.58 mN·m-1.薄层色谱和显色反应表明,XDF-4产出的表面活性剂主要包含:糖类50.26%(质量)、脂类28.47%(质量)、蛋白质15.35%(质量);其临界胶束浓度为22 mg·L-1.GC气相色谱和族组分柱色谱分析表明,烃降解菌Geobacillus sp.XDF-4作用后,原油轻质组分含量明显增加,重质组分含量降低.物理模拟实验表明,该菌可在一次水驱基础上进一步提高采收率5.69%,可有效应用于高温高盐油藏微生物驱现场实验.     

一株耐盐石油烃降解菌的分离、鉴定及其降解特性研究

研究通过逐渐提高培养液的盐浓度从含石油烃的钻井泥浆中驯化获得四株耐盐的石油烃降解菌,筛选出1株对原油降解效率高的优势菌株SW-1。经16S r RNA基因序列分析确定其系统发育地位,采用单因素实验研究环境因素对该菌原油降解率的影响,研究其对典型石油烃类物质的降解能力及降解特性。结果表明:石油烃降解菌耐受的盐度为9%;盐度为0时,菌株SW-1的原油降解率为51.49%; 16S r RNA基因序列比对结果显示,该菌株与Bacillus licheniformis MGB70112. 1核苷酸序列相似性为100%; p H值为9,温度为30℃降解效果最佳;在9%盐浓度,最佳条件下培养7 d,SW-1菌株对原油的降解率为33. 10%,对菲的降解率为46. 53%; GC-MS分析结果表明,菌株SW-1可以降解链长为C19～C28的烷烃,C19～C28烷烃的平均降解率达到18. 48%。     

一株耐盐菌的分离及其降解特性

煤化工废水是一种含盐量较高的难降解工业废水,为了提高其生化处理的效果,从某煤化工企业生产污水中分离得到一株耐盐菌CCZU-R6,经形态观察和16S rDNA序列分析,鉴定该菌株属于芽孢杆菌属(Bacillus sp.)。采用单因素实验方法考察了pH、温度、接种量、废水盐度等工艺条件对降解模拟含盐废水的影响,确定了菌株CCZU-R6处理模拟含盐废水的最适条件为pH 7.0、温度35℃,接种量500mg/L,能耐受的最高盐度约为11%。底物谱分析显示菌株CCZU-R6对苯酚、苯甲醇、甲醇等物质具有显著的降解效果。在最适降解条件下,菌株CCZU-R6处理实际煤化工含盐废水24h,COD去除率达到93%。表明该菌株对含盐煤化工废水有较强的降解能力,具有工业应用前景。     

一株中度嗜盐菌Salinicola sp.在高盐环境中的烷烃降解特性

从青海油田附近被石油污染的土壤中分离得到一株可利用原油为唯一碳源的菌株,将其命名为X4菌株。经16SrDNA分析鉴定,该菌株与中度嗜盐菌Salinicola zeshunii strain N4^T（GenBank序列号为EU056581）同源性高达99%。X4菌株的最适温度为30℃,最适盐度为8%,最适pH为6.5,最佳碳源为甘油,最佳氮源为氯化铵。该菌可产生生物乳化剂,具有较强的细胞疏水性,对正辛烷、十六烷、二甲苯等典型烃类物质具有良好的乳化能力,细胞CSH值达到60%以上。在含5%盐度的无机盐培养基中,以3g/L的柴油为唯一碳源,采用GC-MS定量分析X4菌株的烃降解特征,结果表明菌株X4培养5天后柴油的总降解率达56%,菌株X4优先降解中长链烃类;C₇～C₁₃烃类的平均降解率为64.1%,C₁₄～C₂₀烃类的平均降解率为52.3%,C₂₁～C₃₁烃类的平均降解率约26.8%。离子型表面活性剂TTAB和SDS对X4菌株生长具有较强的毒性：在浓度达到100mg/L和400mg/L时能完全抑制菌体生长;在40mg/L的浓度下,使得菌株对柴油的降解率降低到20%。而X4菌株对非离子型表活剂——吐温80和生物表面活性剂——鼠李糖脂的耐受浓度均可达400mg/L。鼠李糖脂是嗜盐菌X4菌株的合适复配表活剂。     

一株石油烃降解菌的固定化及其降解特性研究

从石油污染盐渍土壤中筛选出一株对液蜡乳化效果明显、对原油降解率达56.8%的菌株,命名为BZ-L。经生理生化和16SrRNA序列分析,初步鉴定该菌株属于沙雷氏菌属。以海藻酸钠和活性炭为包埋剂,对该菌株进行固定化研究。结果表明,当活性炭含量为0.8%时,固定化微球的破损率最低、渗透性最好;在接种量为35.0g·L-1、NaCl浓度为6.0%时,固定化微球对原油的降解率可达61.7%;菌株BZ-L的固定化微球对原油的降解率明显高于游离菌,且比游离菌的耐盐性能更强,可用于石油污染盐渍土壤的生物修复。     

耐盐苯胺降解菌的降解特性研究

本文利用实验室自筛的苯胺降解菌种CLX-6作为出发菌,分别研究对菌种降解苯胺起显著作用的环境因素(盐度、苯胺耐受浓度、温度、氧气等),最终优化的数据如下:菌种耐受盐度含量4%,苯胺耐受浓度为1000mg/L,最适溶氧为摇床转速50r/min,最适温度为30℃,在此优化条件下苯胺降解率86.2%。     

一种大温差耐温耐盐缓凝剂的合成及性能评价

以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酸(AA)、二烯丙基二甲基氯化铵(DMDAAC)为单体,改性蒙脱土为活性填料合成了一种有机-无机复合型大温差缓凝剂(PMC-180)。利用FTIR、XRD和TG对产物进行了结构表征,并对其应用性能进行了评价。结果表明:PMC-180具有插层剥离复合结构,初始热解温度为267.27℃。含PMC-180的水泥浆在90~180℃耐温缓凝性能和抗盐性能良好,初始稠度低于30 Bc,稠化时间可调,曲线平稳无鼓包等异常现象;含PMC-180的24 h水泥石低温强度高于14 MPa,满足长封固段固井要求。PMC-180的缓凝机理及大温差适应机理为:PMC-180通过吸附屏蔽及络合抑制作用延缓Ca(OH)_2晶核、晶体生长;PMC-180片层间距随温变化及阴阳离子竞争吸附减缓低温过渡吸附,使PMC-180具有良好的大温差适应性。     

耐温耐盐预交联凝胶颗粒的性能研究

针对常规调驱剂在裂缝性高温、高盐油藏调驱效果差的难题,以丙烯酰胺、衣康酸、二甲基二丙烯酰胺基磺酸钠为聚合单体,以过硫酸铵和亚硫酸氢钠为氧化还原引发剂,N,N-亚甲基双丙烯酰胺为化学交联剂,锂皂石为物理交联剂,合成了一种耐温、耐盐预交联凝胶颗粒KY-2,并对其微观形貌进行了表征,分析了化学交联剂质量分数对预交联凝胶颗粒吸水性能的影响,评价了其耐温耐盐性能、抗剪切性能和调驱性能。结果表明:颗粒的吸水速率随着交联剂质量分数的增加而降低,该颗粒具有很好的耐温耐盐性和抗剪切性能,在渗透率级差为4的条件下,水驱后提高采收率幅度达15.5%。预交联凝胶颗粒KY-2对裂缝性高温高矿化度非均质油藏具有较强的适应性。     

一株甲醇降解菌Methylobacterium sp.SDM11的筛选鉴定及生长条件优化

从活性污泥中筛选到一株可利用甲醇为唯一碳源和能源生长的细菌SDM11,该菌革兰氏染色阴性,短杆状.经16S rDNA序列比对分析发现,与Methylobacterium sp.的部分16S rDNA同源性达98%.结合其形态特征和生理生化特性,该菌被初步鉴定为甲基营养菌属.在培养温度为30℃、甲醇含量为0.6%、pH值为7.0的最适生长条件下,菌体对甲醇的降解率可达82.5%.     

石油烃降解菌的初筛及其降解性能研究

本文以柴油和石蜡混合物为碳源,利用液体培养基富集培养石油烃类降解菌。得到的菌液通过DCIP显色实验和原油模拟降解实验初步筛选出13株降解菌菌株,并经过分子生物学的鉴定大部分为不动杆菌属和假单胞菌属。经过摇瓶培养后,HY-3、G6和8号菌对于COD和TOC的去除效果较好,并通过和活性污泥复配后发现8号菌能够有效提升SBR系统的生物处理能力,COD去除率达到90%以上。     

化学修饰啤酒酵母菌对铀的吸附特性

以甲醛为交联剂,将胱氨酸修饰到啤酒酵母菌(SC)上,并采用海藻酸钠和明胶固定化,得到一种新型的生物吸附剂——修饰啤酒酵母菌( MSC).通过红外光谱(IR)分别表征了两种吸附剂的结构,考察了其吸附铀的主要影响因素即溶液pH值、吸附时间等.结果表明:MSC细胞表面具有大量吸附铀的基团,MSC和SC吸附铀的最佳条件是:pH...     

沙雷氏菌Serratia sp.BK-98发酵生产2-酮基-D-葡萄糖酸的工艺优化及动力学研究

Based on the optimization of culture conditions for producing 2-keto-D-gluconic acid(2-KDG)by Serratia sp.BK-98 in a Erlenmeyer flask, the factors of dissolved oxygen(DO)and pH affecting 2-KDG batch fermentation in 100 L fermenter were further optimized to be 30% and 6.0 respectively.Under the DO-stat and pH-stat batch culture conditions, 2-KDG production reached 211.2 g·L^-1.The kinetics of DO-stat and pH-stat batch fermentation were also investigated and the models for biomass, substrate consumption and product were established respectively based on the Logistic equation, Leudeking-Piret equation and Modified Leudeking-Piret equation.Curve fittings for the above models by using experimental data were performed by the non-linear least squares method with the software Origin 8.0.With the evaluated model parameters, the calculated values of the models and experimental data were in good agreement and the models could provide guidance for 2-KDG fermentation production.     

富氧燃烧含灰烟气辐射特性的部分光谱k模型

针对煤粉在富氧燃烧方式下烟气为炭黑、飞灰、高浓度CO2和H2O蒸气混合物的辐射换热问题,建立了描述混合物非灰辐射特性的部分光谱k分布模型.为了验证模型的有效性,以文献中煤粉在富氧燃烧方式下烟气生成状况为例,采用该模型与离散坐标法相结合的方法,计算了一维无限大平行平板、单光谱行程和二维矩形封闭系统内混合物的辐射源项和壁面...     

Investigation on a core–shell nano-structural LiFePO4/C and its interfacial CO interaction

Core–shell LiFePO₄/C nanocomposite has been prepared by a sol–gel method. The mean size of the spherical core LiFePO₄ is about 30 nm, and thickness of carbon shell is about 3 nm. The bonding character on the interface of core–shell was revealed by soft X-ray absorption spectroscopy (XAS). The as-prepared sample was characterized by X-ray diffraction (XRD), Raman spectrum, Transmission electron microscope (TEM) and High-resolution transmission electron microscopy (HRTEM). Charge-discharge tests show the core–shell LiFePO₄/C demonstrates high rate capability (106 mAh g⁻¹ at 20 C) and good cycling performance (negligible capacity loss after 250 cycles).     

A homogeneous redox catalytic process for the paired synthesis of l-cysteine and l-cysteic acid from l-cystine

Redox catalytic process involved in the paired electrosynthesis of l-cysteine and l-cysteic acid from l-cystine is investigated by cyclic voltammetric technique and also confirmed by preparative electrolysis. The cyclic voltammetric behaviour shows that in the catholyte, in situ deposited tin (Sn) surface acts as a redox catalyst for the electro-reduction of l-cystine to l-cysteine whereas in the anolyte, the electro-generated bromine acts as a homogeneous redox mediator to enhance the electro-oxidation of l-cystine. l-Cysteine hydrochloride monohydrate (l-cysteine) and l-cysteic acid are prepared from l-cystine by preparative electrolysis with high purity and high yield using graphite cathode and DSA anode. At optimum concentration of l-cystine with 1:1 concentration ratio (catholyte:anolyte), the material yield obtained for l-cysteine is above 80% and that for l-cysteic acid is close to 60% in the paired electrosynthesis process in the batch operation. Scope for further experiments in conversion efficiency is also discussed.     

Production of a halotolerant lipase from Halomonas sp. strain C2SS100: Optimization by response-surface methodology and application in detergent formulations

The aim of this work was to optimize the production of a new lipase by a halotolerant bacterial strain Halomonas sp. C2SS100, by means of the response-surface methodology (RSM). The process parameters having the most significant effect on lipase production were identified using the Plackett–Burman screening design-of-experiments. Then, Box–Behnken design was applied to optimize lipase activity and the quadratic regression model of the lipase production was built. Indeed, the lipase yield was increased, and the value obtained experimentally (39 ± 2 U/ml) was very close to the rate predicted by the model (40.3 U/ml). Likewise, optimization of parameters by RSM resulted in 2.78-fold increase in lipase activity. These findings provide the first report on lipase production and optimization by a halotolerant bacterial strain belonging to Halomonas genus. Afterward, the biochemical properties of the produced lipase were studied for apply in oil stains removal. The crude lipase showed a maximum activity at 60°C and at pH ranging from 7 to 10. It displayed an important stability at high temperature, pH, and NaCl. Interestingly, this bacterial lipase exhibited a prominent stability toward some commercial solid and liquid detergents after 30 min of incubation at 50°C. The capability of the crude lipase to eliminate stain was ascertained on polycotton fabric pieces stained with lubricating oil. Whether with the addition of hot water alone or of a commercially available detergent, lipase is able to considerably boost the elimination of oil stains. The actual findings highlight the capacity of Halomonas sp. lipase for energy-efficient biocatalytic application.     

Decomposition of chlorofluorocarbons on TiO2ZrO2

The decomposition of chlorofluorocarbons (CFCs) in the presence of water was examined over a variety of solid acid catalysts. The TiO₂ZrO₂ catalyst was found to have the highest activity and longest life among the catalysts examined. The activity of the TiO₂ZrO₂ catalysts depended upon the content of TiO₂. At the contents of TiO₂ from 58 to 90 mole%, the TiO₂ZrO₂ catalysts exhibited high activity, and these catalysts were proven to contain TiZrO₄ crystal. From the study of the XRD peak intensity of the TiZrO₄ crystal, it was highest on the TZ-58 which contained 58 mole% of TiO₂, and decreased with increasing the content of TiO₂. Furthermore, the conversion of CFC113 measured at 673 K was highest at TZ-58, and decreased gradually with increasing TiO₂ content. Therefore, the TiZrO₄ crystal influences the activity of decomposition of CFC113. However, the TiO₂ZrO₂ catalyst was gradually deactivated during the reaction due to the elimination of titanium atoms. A good relationship was found between the activity on TiO₂ZrO₂ catalyst and bond energy of CCl in the compounds of chlorofluorocarbons and hydrochlorocarbons, suggesting that the rate controlling step was the cleavage of CCl bond.     

Solubility of D-p-hydroxyphenylglycine p-toluenesulfonate and L-p-hydroxyphenylglycine in different solvents

The solubility of D-p-hydroxyphenylglycine p-toluenesulfonate and L-p-hydroxyphenylglycine in different solvents was measured using a laser monitoring observation technique. The solubility data were accurately correlated by the modified Apelblat equation, the calculated results of which were proved to show fine representation of experimental data.