Genetic engineering of E-coli SE5000 and its potential for Ni2+ bioremediation

A genetically engineered Escherichia coli SE5000 strain simultaneously expressing nickel transport system and metallothionein was constructed to accumulate Ni2+ from aqueous solution. Bioaccumulation was fast and followed linearized Langmuir isotherm. Compared with 1.62 mg/g of Ni2+ uptake capacity by original host E. coli cells, genetically engineered E. coli could bind 7.14 mg/g Ni2+, and it accumulated Ni2+ effectively over a broad range of pH (4-10) and the optimal pH was 8.6. The presence of 1000mg/l Na+ and Ca2+ or 50 mg/l Cd2+ and Pb2+ did not decrease Ni2+ bioaccumulation significantly, but Mg2+, Hg2+, Cr3+ and Cu2+ posed severe deleterious influences on Ni2+ uptake by genetically engineered E. coli. Furthermore, the presence of EDTA inhibited nickel bioaccumulation. (C) 2004 Elsevier Ltd. All rights reserved

The Preparation of Silver Nanoparticles

［中文文摘］在简要介绍纳米银在各个工业领域应用的基础上,总结比较了各种制备纳米银颗粒的方法。物理和化学方法的工艺技术都比较成熟,但也存在着一定的不足。新兴的生物还原法因其具有微生物原料来源广,生物还原反应条件温和,产物纳米颗粒不易团聚,以及过程加入的化学试剂和产生的有毒副产物少等特点而开始受到关注。微生物还原金属离子有2种不同的机理:微生物的酶催化机理和非酶还原机理。对生物还原法原理的充分认识是将该方法发展成为可实际应用的纳米银制备工艺的重要基础。［英文文摘］The main applications of silver nanoparticles in industry were briefly reviewed in the present paper. The methods used for preparation of silver nanoparticles were summarized and compared. The physical and chemical methods are relatively mature but they have some shortcomings. The biological method is recently developed as a promising method because of its special advantages such as sufficient material sources, mild reaction conditions, good dispersion of nanoparticles as well as few chemical addictives and poisonous byproducts. The biological method for preparation of silver nanoparticles included two mechanisms, namely enzymatic catalysis mechanism and non-enzymatic reduction mechanism. The full understanding of two mechanisms would be necessary for developing it into a practical process to prepare silver nanoparticles.国家自然科学基金(20376076); 中国石油化工股份有限公司项目(0041-K81042)

生物法制备纳米银溶胶的稳定性

利用生物还原法制备纳米银溶胶,借助于UV-Vis表征技术对其热稳定性和化学稳定性进行考察。结果表明:生物法制备的纳米银溶胶在100℃下加热6h,UV-Vis谱图未发生明显变化;H+和具有高价阳离子的电解质对其稳定性的影响明显;OH-对银溶胶的稳定性影响相对较弱。生物法制备的纳米银溶胶在热稳定性、化学稳定性方面均略优于柠檬酸三钠法制得的银溶胶

袋鼠皮蛋白肽对H2O2诱导人肝细胞LO2氧化损伤的影响

为探索袋鼠皮蛋白肽如何修复受H2O2损伤的LO2细胞,通过建立H2O2诱导人肝细胞LO2氧化损伤的模型,研究袋鼠皮蛋白肽对氧化应激损伤的人肝细胞LO2的修复作用。结果表明:袋鼠皮蛋白肽在0～0.5μg/μL浓度范围内不仅对LO2细胞活性没有抑制作用而且显著提高了受损细胞的存活率,改善了细胞的形态;与此同时,显著降低了H2O2诱导的丙二醛释放,降低了蛋白质羰基含量和活性氧的水平,使细胞受氧化损伤的影响减小。厦门大学横向课题(XDHT2017407A);;福建省博胜生物科技有限公司项

Production of β-glucanase by cultivation of immobilized recombinant E.coli cells in a packed bed reactor

以多孔陶瓷为载体吸附法固定重组大肠杆菌E.coli JM 109-pLF3表达胞外β-葡聚糖酶。考察了固定床间歇培养时循环流速和曝气量对发酵液酶活力的影响。当循环流速达到44.19mL/min,曝气量达到0.6mL/min时,培养48h后,发酵液的酶活力达100.3U/mL。固定化细胞具有良好的重复使用能力,在连续5批次实验中,培养48h后的酶活力均在100U/mL左右。固定床连续培养时,固定化细胞能够保持恒定的产酶效率,当稀释率为0.05h-1时,发酵液中得到的酶活力为39.1U/mL。β-glucanase produced by immobilized Escherichia coli JM 109-pLF3 in a packed bed bioreactor was studied.In batch fermentation,the highest enzyme activity of 100.3 U/mL was achieved at a recycling rate of 44.49 mL/min and an aeration rate of 0.6 mL/min after 48 h cultivation.In repeated batch operation,the enzyme activity up to 100 U/mL was obtained in 5 cycless,howing high stability of the immobilized cells.In continuous fermentation,the production of β-glucanase by immobilized cells was kept more or less constant.When the dilution rate was 0.05 h-1,the enzyme activity in the fermentation broth was 39.1 U/mL.厦门市科技计划项目(No.3502Z20055017

Treatment of Purified Terephthalic Acid Wastewater by Sequencing Batch Reactor

［中文文摘］采用序批式反应器(SBR)处理模拟精对苯二甲酸(PTA)废水,考察了曝气量、沉降时间、进水方式等对对苯二甲酸(TA)生物降解效果的影响。实验结果表明,对于TA质量浓度小于1 500m g/L的废水,采用完全曝气SBR运行4h,TA和COD的去除率均能达到95%以上,TA平均去除速率随TA浓度的增加而增大。TA质量浓度为1 500m g/L时,曝气量、沉降时间和进水方式是影响其降解效果的主要因素。采用SBR处理高浓度PTA废水可克服污泥膨胀和抗冲击负荷能力弱的问题,且系统的稳定性和PTA废水的处理效果较好。［英文文摘］Simulated purified terephthalic acid(PTA)wastewater was treated by sequencing batch reactor(SBR).The effects of aeration rate,settling time,feeding mode on the biodegradation of terephthalic acid(TA)were investigated.When the mass concentration of TA is less than 1 500mg/L,the removal rate of TA and COD are both more than 95% after aerating for 4h in SBR.The average TA removal rate increases with the increasing of TA mass concentration.When the mass concentration of TA is 1 500mg/L,the main factors affec ting degrada tion are aeration rate, settling time and feeding mode. Treating high concentration PTA was tewater by SBR can solve the problems of sludge bulking and lack of shock load resistance cap ability, and the system has a good stability and treatment effect for PTA wastewater.国家自然科学基金资助项目(20076037

Green Synthesis of Potassium Diformate

以甲酸和氢氧化钾为原料,不外加任何溶剂一步合成二甲酸钾。通过单因素实验,考察了原料配比、反应温度和反应时间对产品质量与收率的影响。采用正交实验进一步优化了合成工艺,确定了最佳工艺条件:n(HCOOH)/n(KOH)=2.2、反应温度70℃、反应时间30 m in,在该条件下,二甲酸钾产品收率达98%以上。所得产品经红外光谱分析及熔点测定,其结果与文献报道一致。反应过程绿色化,有很好的原子经济性。Potassium diformate was synthesized without solvent,using formic acid and potassium hydroxide as raw materials.The optimal conditions for the reaction were:molar ratio of HCOOH to KOH 2.2∶1,reaction temperature 70 ℃ and reaction time 30 min.Yield of the process was over 98% under the optimal conditions.The infrared spectrum and melting range of the product were in good agreement with those reported in literature.The technology developed in this study could be an environmentally benign synthesis route with efficient atom economy

贵金属纳米颗粒及其催化剂的生物还原制备技术

利用自行筛选的具有强还原能力的菌株制备得到银纳米颗粒,所得颗粒的粒径基本在10 nm以下,主要集中在2~8nm。将生物还原过程进一步引入催化剂制备过程,得到负载型银催化剂和负载型钯催化剂,并将催化剂分别应用于1,2-丙二醇空气氧化合成丙酮醛、CO氧化生产CO2以及蒽醌加氢反应中

Improving the Expression Level of Soluble Human Fas Ligand by Cultivating Recombinant Dictyostelium discoideum in CMC-ALG Microcapsules

首先研究了应用于液芯羧甲基纤维素钠-海藻酸钙(CMC-ALG)微胶囊制备中的各种化学组分对重组盘基网柄菌生长的影响,然后考察不同组分浓度制备而成的各种CMC-ALG微胶囊内重组盘基网柄菌的生长情况,从而得到较适的微胶囊制备的组分配比(CMC12g·L-1,SA8g·L-1,CaCl2100g·L-1)。结果表明,在以上较适条件下制备的微胶囊内重组盘基网柄菌的生长得到了极大的改善,最大的细胞密度比游离培养时提高了4倍,达到了8.0×107mL-1;相应的人类可溶性Fas配体(FasL)的表达水平也提高了1.5倍,达到了315μg·L-1。最后,开展了微胶囊化重组盘基网柄菌的二次重复发酵FasL的研究,结果表明,经过二次重复批次培养,最大细胞密度可达到1.24×108mL-1,为游离培养的8～10倍,而且FasL的表达水平还能维持高水平(280μg·L-1),为游离培养时的2倍。The biocompatibility between the growth of Dictyostelium discoideum AX3-pLu8 and chemical components used for the preparation of carboxy methyl cellulose-alginate(CMC-ALG)microcapsules was evaluated at first,and then the effects of the concentrations of each component forming the capsule on the growth behaviors of D.discoideum cultivated in it were studied.For microencapsulated cultivating D.discoideum,it was found that the most suitable capsule components are 12 g?L?1 of CMC,8 g?L?1 of sodium alginate(SA)and 100 g?L?1 of CaCl2.Using the microcapsules with mentioned composition,the cell density in it can reach 8.0×107 mL?1,this value is about 5 times that could be observed in suspension culture,and correspondently,in the capsules a high concentration(315 μg?L?1)of soluble human Fas ligand(shFasL)was detected,which is about 2.5 times higher than that obtained in suspension culture under the same culture condition.In addition,the immobilized cells could be used effectively for repeated batch cultivation and in the second repeated batch cultivation,a very high cell density(up to 1.24×108 mL?1)and still a high expression of FasL(280 μg?L?1)could be obtained.国家自然科学基金资助(20306025,30370039

微波辅助萃取-大孔树脂分离纯化芳樟叶黄酮

为了综合利用芳樟叶精油提取过程中产生的大量残渣,该文利用微波辅助萃取和大孔树脂选择性吸附来分离纯化芳樟叶黄酮。采用L9(34)正交试验,考察了萃取剂、微波辐射功率、辐射时间及料液比对黄酮得率的影响,确定了微波辅助萃取的优化工艺条件:以60%乙醇做萃取剂,微波功率320W,间歇辐射2次,每次1min,料液质量体积比1:12,在此条件下,芳樟叶黄酮的提取得率为2.97%,与乙醇热回流提取方法相比,得率提高了6.83%,时间缩短了98.89%;为进一步纯化萃取所得的黄酮提取物,选择6种大孔吸附树脂,测定芳樟叶黄酮在树脂上的吸附量和解吸率,筛选出了吸附剂HPD-450,其对芳樟叶黄酮有较好的静态吸附和解吸效果。经装填有大孔树脂HPD-450的固定床纯化后黄酮纯度由22.49%提高到51.28%,纯化倍数2.3倍