沸石固定化细胞降解氰化物的实验研究

利用本实验室保藏的一株产碱杆菌DN25作为降氰菌株,以沸石为载体进行固定化,研究了固定化细胞的降解特性。实验表明采用吸附生长法能有效实现菌株DN25在沸石上固定化,生物固定量可达到0.228g干细胞·(gzeolite)?1。固定化细胞的最适降解温度为30℃,最适pH为8.0,与游离细胞基本一致。将固定化细胞分别用于50mgCN?·L?1和500mgCN?·L?1的含氰液的降解,发现对于低浓度含氰废水固定化细胞的初始降解率仅为游离细胞的一半,而对于高浓度氰废水,固定化细胞的降解速率与游离细胞基本相同。固定化细胞可重复使用10天,降解率仍能达到90%。     

Chitosan‐coated alginate–polyvinyl alcohol beads for encapsulation of silicone oil containing pyrene: a novel method for biodegradation of polycyclic aromatic hydrocarbons

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) are potential hazards in the environment owing to their toxic, carcinogenic and recalcitrant nature. Biodegradation of these compounds, although effective compared with other treatment techniques, is problematic owing to its low aqueous solubility and negligible bioavailability. The present study reports a novel method for biodegradation of PAHs using an encapsulated form of the pollutant in chitosan‐coated alginate–polyvinyl alcohol (PVA) beads. RESULTS: A suitable combination of 3% (w/v) PVA, 100 g L^?1 non‐ionic surfactant Brij 30 and 0.3 silicone oil fraction in the formulation was found to be optimal in the preparation of stable emulsion. The emulsion obtained was admixed with alginate (3% w/v) to prepare suitably sized microspheres by an emulsion gelation technique, which were later coated with chitosan to yield a maximum pyrene encapsulation efficiency of 90.7%. Pyrene in silicone oil at concentration as high as 2 g L^?1, when delivered through the chitosan coated alginate–PVA beads, was completely degraded by Mycobacterium frederiksbergense within 10 days without any significant lag phase. CONCLUSION: Using chitosan‐coated alginate–PVA beads sustained release of pyrene and subsequent biodegradation by M. frederiksbergense were achieved. Using the present system, complete degradation of pyrene was attained even at its very high initial concentration and within a short time period. Further advantage offered by this system seems to be negligible toxic effect of pyrene and solvents on the degrading microorganisms since these were in an encapsulated form and were not in direct contact with the organism. Copyright © 2010 Society of Chemical Industry     

固定化白腐真菌降解焦化废水的动力学研究

采用木屑固定化白腐真菌并对焦化废水进行处理,有机物降解的宏观动力学符合一级反应动力学,动力学模式为lnS=-Kt＋lnS0。在15~30℃范围内反应速率常数K随温度升高不断增大,在30~40℃范围内反应速率常数K随温度升高不断降低,在30℃时反应速率常数最大K=0.0265 h-1。     

固定化Pseudomonas delafieldii R-8细胞同时脱除噻吩和二苯并噻吩(英文)

Biodesulfurization(BDS) is a promising technology for deep desulfurization.In this work,Pseudomo-nas delafieldii R-8 cells are immobilized in calcium alginate beads and used for BDS of transportation fuels.It is found that thiophene and dibenzothiophene(DBT) can be simultaneously metabolized by immobilized R-8 cells.The initial sulfur content in the model oil is 300 mg?kg?1(thiophene︰DBT 1︰1).After 10 h of treatment,the thiophene concentration is reduced by 40%,while DBT is reduced by 25%.The utilization rate of thiophene is faster than that of DBT.Moreover,the oil/water ratio of alginate immobilized cells is studied to reduce the water volume in desulfurization systems.Long-term recycling of BDS by alginate immobilized cells is carried out with oil/water ratio at 5︰1.The immobilized cells are successfully reused over 15 batch cycles.In the last batch,the desulfurization activity remains at least 75% of the first batch.     

Removal of Persistent Sulfamethoxazole and Carbamazepine from Water by Horseradish Peroxidase Encapsulated into Poly(Vinyl Chloride) Electrospun Fibers

Enzymatic conversion of pharmaceutically active ingredients (API), using immobilized enzymes should be considered as a promising industrial tool due to improved reusability and stability of the biocatalysts at harsh process conditions. Therefore, in this study horseradish peroxidase was immobilized into sodium alginate capsules and then trapped into poly(vinyl chloride) electrospun fibers to provide additional enzyme stabilization and protection against the negative effect of harsh process conditions. Due to encapsulation immobilization, 100% of immobilization yield was achieved leading to loading of 25 μg of enzyme in 1 mg of the support. Immobilized in such a way, enzyme showed over 80% activity retention. Further, only slight changes in kinetic parameters of free (K_m = 1.54 mM) and immobilized horseradish peroxidase (K_m = 1.83 mM) were noticed, indicating retention of high catalytic properties and high substrate affinity by encapsulated biocatalyst. Encapsulated horseradish peroxidase was tested in biodegradation of two frequently occurring in wastewater API, sulfamethoxazole (antibiotic) and carbamazepine (anticonvulsant). Over 80% of both pharmaceutics was removed by immobilized enzyme after 24 h of the process from the solution at a concentration of 1 mg/L, under optimal conditions, which were found to be pH 7, temperature 25 °C and 2 mM of H₂O₂. However, even from 10 mg/L solutions, it was possible to remove over 40% of both pharmaceuticals. Finally, the reusability and storage stability study of immobilized horseradish peroxidase showed retention of over 60% of initial activity after 20 days of storage at 4 °C and after 10 repeated catalytic cycles, indicating great practical application potential. By contrast, the free enzyme showed less than 20% of its initial activity after 20 days of storage and exhibited no recycling potential.     

SA-CMC固定反硝化细菌好氧反硝化性能探究

为扩大反硝化菌应用和抗逆性,以海藻酸钠(SA)和羧甲基纤维素钠(CMC)为载体、用CaCl2交联,联合包埋脱氮副球菌,制作反硝化菌剂,探究有氧条件下,菌剂的好氧反硝化性能.结果表明,有氧条件下,所得菌剂对硝态氮的还原能力显著高于游离态菌(总氮氧化物去除率分别为95.6％和9.6％).CMC含量升高能显著提高菌剂好氧反硝...     

Biodegradation of High Strength Phenolic Wastewater in a Modified External Loop Inversed Fluidized Bed Airlift Bioreactor (EIFBAB)

An EIFBAB was modified with a mixed‐tank reactor placed in series to extend the phenol treatability range. Phenol degradation at high concentrations was investigated at recycle rates from the mixed‐tank reactor from 0 to 15 L/h under batch operation. With a total working volume of 10 L, the new setup could handle 3000 mg/L phenol at a comparable volumetric biodegradation rate of 9 mg/L·h at optimized operation of 5 L/h recycle rate, as the 11 mg/L‐h in the original EIFBAB. While the original EIFBAB could not handle phenol concentrations exceeding 3000 mg/L, continuous operation was ascertained in the modified EIFBAB for phenol degradation of up to 5000 mg/L phenol and feed flow rates up to 160 mL/h. The recoverability of the system under shock loading of phenol up to 5000 mg/L was also assessed.     

固定化菌种降解丁二腈的研究

分别用海藻酸钠与聚乙烯醇为载体,对前期研究中获得的丁二腈高效降解菌进行包埋固定。研究了不同载体包埋固定的菌种对废水中丁二腈的降解效果。结果表明,采用海藻酸钠包埋固定的菌种在30℃,pH=6.5,摇床转速为250r/min的条件下,当菌的质量浓度为lg/L和2g/L时,丁二腈的降解率均达80%以上。     

润滑油生物降解菌的筛选

以被石油基润滑油污染的土壤为出发菌源,通过增加环境选择压力的方法,驯化、筛选分离出对石油基润滑油具有一定降解能力的菌株RHY-1,该菌株的100 mL菌悬液48 h对5 mL润滑油的降解率为82.4％,可生长的pH值范围为3.0～11.0,可耐受的NaC1浓度为27 g·L-1;在30℃、pH值为8.0、NaCl浓度为...     

微囊固定化东北红豆杉细胞的生长与代谢

通过对海藻酸钠-壳聚糖液芯、固芯胶囊包埋的东北红豆杉细胞生长与代谢的比较研究,发现液芯胶囊包埋的细胞存活率大于固芯胶囊,对糖类等营养物质的吸收好于固芯胶囊,更有利于包埋细胞的初生代谢. 同时发现,海藻酸钠-壳聚糖固芯、液芯胶囊包埋均利于次级代谢产物等胞内物质向胞外释放,尤其是液芯胶囊的促释作用更为明显,且其酚类物质合成与分泌增多. 结果表明,液芯胶囊包埋植物细胞是一种较为理想的微囊固定化植物细胞的方法.     

甲壳素生物降解制备低聚氨基葡萄糖

低聚氨基葡萄糖是具有调控植物生长、防治植物病害、调节人体免疫、抑制肿瘤等功能的寡糖原料产品。应用低聚氨基葡萄糖研制的生物农药“好普”对水果、蔬菜病害的防治效果达到80％以上,研制的保健食品“奥利奇善”胶囊和“派其安”胶囊具有调节免疫及促进排铅的作用,已实现产业化。     

固定化细胞生物反应器处理含氰废水

将产碱杆菌Alcaligenes sp.DN25固定在聚氨酯泡沫载体上构成固定化细胞反应器,进行连续处理含氰废水研究.实验结果表明,反应器能够高效且稳定地处理含氰废水,有很好的氰负荷适应性,水力停留时间HRT和pH值对反应器氰去除率有一定影响,反应器运行前40 d降解率维持在90%;运行的40～60 d,系统中加入氨氮离子后,反应器对氰化物的降解率明显下降,仅85%左右,我们认为是氨氮连续加入和产物HCOOH的生成引起系统缓冲能力下降,使得pH显著降低而造成.     

无溶剂体系中共吸附固定化脂肪酶催化合成植物甾醇酯

以大孔树脂NKA吸附固定化脂肪酶为催化剂,以月桂酸和植物甾醇为反应物,在无溶剂体系中合成植物甾醇酯;以NKA为载体共吸附固定葡聚糖与酶,考察了反应温度、底物摩尔比、糖种类及葡聚糖添加量和反应时间对酶催化性能的影响. 结果表明,在酸/醇摩尔比6:1、葡聚糖与酶共同吸附固定时分子量为10 kDa的葡聚糖添加量为酶量7.5%的条件下,60℃下反应12 h,酯化率高达96.2%,酯化反应时间比简单吸附固定化酶缩短4 h.     

辣根过氧化物酶生物降解五氯酚

采用辣根过氧化物酶催化降解五氯酚(PCP),探讨了pH值、温度、n(H2O2):n(PCP)和酶用量等因素对五氯酚去除率的影响.通过向反应体系中投加非离子型表面活性剂Tween-40,增强了辣根过氧化物酶的稳定性,延长了酶活性时间,并对其作用机理进行了探讨.实验表明非离子型表面活性剂Tween-40能够提高五氯酚的去除率,降低处理成本.     

Peptide Vectors Carry Pyrene to Cell Organelles Allowing Real-Time Quantification of Free Radicals in Mitochondria by Time-Resolved Fluorescence Microscopy

Real-time quantification of reactive nitrogen and oxygen species (ROS) in cells is of paramount importance as they are essential for cellular functions. Their excessive formation contributes to the dysfunction of cells and organisms, ultimately leading to cell death. As ROS are mostly produced in the mitochondria, we have synthesized a fluorescent probe able to reach this organelle to detect and quantify, in real time, the variation of ROS by time-resolved microfluorimetry. The new probes are based on the long fluorescence lifetime of pyrene butyric acid (PBA). Two PBA isomers, attached at their 1- or 2-positions to a peptide vector to target mitochondria, were compared and were shown to allow the measurement of free radical species and oxygen, but not non-radical species such as H₂O₂.     

固定化细胞技术的研究进展

介绍了固定化细胞技术和近年来固定化细胞的制备方法、影响因素、载体特性等内容,探讨了固定化细胞技术在废水处理中的应用现状与今后的研究和发展方向。     

固定化细胞载体材料的研究进展

固定化细胞技术是在固定化酶的基础上发展起来的高新技术,所用载体材料的性能是此项技术的关键。详细介绍了固定化细胞技术中常用载体材料的种类及其性能,概述了新近出现的载体材料及其应用,最后对载体材料的未来发展进行了预测。     

混合培养微生物降解氯氰菊酯的特性研究

通过富集培养,获得了降解氯氰菊酯的混合微生物。结果表明,该混合微生物发挥最优降解力的温度是35℃,pH为7.5,培养时间为72h。氯氰菊酯降解速度和混合培养微生物生长对外加碳源有较强的依赖性。培养液中添加5g.L-1葡萄糖和3g.L-1酵母粉,72h氯氰菊酯去除率可达80%以上,氯氰菊酯降解速率可达0.56mg.L-1.h-1;当氯氰菊酯作为培养菌生长的唯一碳源、氮源和能源时,72h内氯氰菊酯去除率为65%,降解速率为0.45mg.L-1.h-1。     

一种选择性拆分布洛芬对映体的固定化脂肪酶

为了提高扩展青霉TS414脂肪酶(PEL)对布洛芬的拆分效率,建立了适于非水相中选择性拆分(R,S)-布洛芬的固定化方法. 结果表明,固定化介质的类型、冻干pH和外加水量等因素对固定化PEL酶促拆分(R,S)-布洛芬有较大影响. 在冻干pH为9.0、外加水量为0、以大孔吸附树脂AB-8为固定化载体的体系中,40℃反应30 h后,拆分反应的转化率可达47%,对映体过量值eeP可达98.75%. AB-8固定化后,PEL在有机相反应体系中的分散性得到了明显改善,大幅度提高了酶促拆分反应的效率;大孔吸附树脂AB-8固定化PEL具有较高的操作稳定性,连续10批拆分反应的平均转化率在47%以上,eeP值均稳定在98%以上.     

Models for the Biodegradation Kinetics of Naphthalene by Ralstonia Eutropha

Biodegradation of naphthalene (naph.) by a pure culture of Ralstonia eutropha was studied. Dissolution of naph. in aqueous solution was provided by using Tween-80 nonionic surfactant. By developing the solubility curve, the molar solubility ratio (MSR) was determined (0.8081). The effects of Tween-80, initial-pH, and naph. concentration on the R. eutropha growth and its naph. degradation capability were investigated. Degradation of naph. at 50 mg/L was complete within 52 h in the presence of 1.6 mM Tween-80 at pH 7. Haldane, Webb, Aiba, and Edwards, as the growth inhibitory kinetic models, were used to mathematically describe the inhibitory characteristic of naphthalene and the results were evaluated using nonlinear regression technique. The values of root mean square error (RMSE) and the correlation coefficient (R²) showed appropriateness of approach taken in the present study (RMSE≈ 3×10^?3, R²≈ 0.99). Importance of the mechanistic view of these types of mathematical models has been emphasized.