有机相酶催化

有机相酶催化是酶工程研究最为活跃的领域之一。本文综述了水及有机溶剂对有机相酶催化过程中酶的活性，稳定性，底物特异性，反应平衡等的影响；酶在有机溶剂，离子，赋形剂等的影响下的构象变化及性质改变的原因；评述了这一领域的应用现状和今后发展方向。     

有机污染物降解用光催化纸的研究进展

介绍利用造纸技术制备有机污染物降解用光催化纸,光催化纸集中了悬浮TiO2和固定TiO2两者的优点,为TiO2在环境污染治理中的应用开辟了一个新的研究领域,另外还介绍了光催化纸对气相和液相有机污染物的研究进展。     

利用漆酶降解有机污染物

漆酶是近年来在造纸界研究研究比较多的一种降解木素的氧化还原酶。本文对影响漆酶转化去除环境中有毒污染物能力的因素、漆酶脱氯去除氯酚化合物毒性的机理及其在处理含酚废水中的应用进行综述。     

基于生物滤床的有机污染物降解机制

随着我国城乡人民生活水平的提高,城市河流污染情况严重,黑臭污染问题日益突出。由于地下管网昂贵,乡镇地区等分散地区排放污水短期无法建立下水道设施集中处理。从新农村建设角度出发,需要在城乡大力推广生物生态治理方法,促进生态环保可持续发展。为消除城市黑臭水体,采用复合生物酶对黑臭河流水样进行小试,结果表明喷洒复合生物酶优化质量浓度为10mg/L,在污水接近中性的状态下有利于提高处理效果。采用生物滤床技术对黑臭河流进行中试,结果表明喷洒复合生物酶优化质量浓度为10mg/L。配合水生植物处理BOD5含量满足GB3838-2002地表水V类标准要求。复合生物酶可促进生物滤床降解污染物。     

有机污染物降解用光催化纸的应用与展望

该文介绍了利用造纸技术制备有机污染物降解用光催化纸,光催化纸集中了悬浮TiO2和固定TiO2两者的优点,为TiO2在环境污染治理中的应用开辟了一个新的研究领域。文章介绍了光催化纸对气相和液相有机污染物的研究进展。     

基于封装酶的金属有机框架纳米酶级联催化实现鱼肉中次黄嘌呤的可视化检测

目的 基于金属有机框架(metal-organic framework, MOF)封装黄嘌呤氧化酶(xanthine oxidase, XOD)构建纳米酶级联催化体系, 实现次黄嘌呤(Hypoxanthine, Hx)的可视化检测。方法 室温下采用一步法仿生矿化工艺将天然酶XOD封装于1,4-苯二甲酸铜(copper 1,4-benzenedicarboxylate, CuBDC) MOF纳米酶中, 制备封装酶的金属有机框架材料(XOD@CuBDC), 探究其过氧化物酶活性及级联催化性能。通过最适反应条件的优化, 建立颜色强度与Hx浓度的标准曲线, 考察该方法对鱼肉中Hx的检测。结果 与使用游离XOD和CuBDC组成的级联反应系统比较, XOD@CuBDC催化速度更快, 显色强度更强, 酶储存更稳定。该体系的颜色强度与Hx浓度在0.015~0.470 mmol/L范围内具有线性关系(R2>0.99), 方法检出限(S/N=3)为10.47 μmol/L。应用于不同新鲜程度的牙鲆鱼肉中Hx含量测定, 结果与高效液相色谱法(high performance liquid chromatography, HPLC)呈线性关系, 相关性为0.98865。结论 构建的XOD@CuBDC纳米酶级联催化体系具有良好的稳定性和催化性能, 能够用于鱼肉中Hx的快速检测。     

木素降解酶在制浆漂白中的应用

木素降解酶的生物漂白是通过木素降解酶的直接氧化和降解纸浆中的残余木素,以降低纸浆的卡伯值,提高纸浆白度或有利于后续化学漂白剂的漂白,提高可漂性.本文着重介绍了三种木素降解酶在漂白中的应用.     

Characterization of toxic effects of sediment-associated organic pollutants using the lambda transgenic medaka

A novel sediment-contact assay using embryos of the transgenic medaka was developed to fully characterize the toxic effects induced by exposure to a mixture of organic pollutants in sediments. Embryos of the lambda transgenic medaka were exposed for 10 days to a clean reference sediment spiked with either the solvent alone, benzo[a]pyrene (B[a]P), or three concentrations (0.3x, 1x, and 2x) of an organic extract (OE) of sediments from the Seine estuary. The 1 x OE-spiked sediment contained concentrations of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls similar to those in field-collected sediment. Exposure to this sediment, but not to the B[a]P-spiked sediment, significantly increased embryo-larval mortality and prevalence of spinal deformities. Mutant frequency at the cII mutation target gene in the liver of 10-week-old medaka was significantly increased following exposure to either B[a]P or the three doses of OE. The predominant OE-induced liver mutations were G:C to T:A transversions, consistent with PAHs being the major contributors to the mutation induction. Liver and gonadal tumors were observed in 35-week-old medaka exposed to either B[a]P (1/25) or to the 1 x OE (1/24). The benefits of medaka as a fish model for toxicological assessment and the benefits of the cII mutation assay for mutation detection combine to provide comprehensive assessment of a wide range of genotoxic and nongenotoxic effects of aquatic pollutants.     

Research Watch: Persistent organic pollutants

Contaminants.     

Biodegradation of phenolic environmental pollutants by a surfactant-laccase complex in organic media

Oxidative degradation of phenolic environmental pollutants in organic media was investigated using a laccase complexed with surfactants. The catalytic activity of the surfactant-laccase complex in isooctane was markedly enhanced by appropriately adjusting the water content of the reaction medium using reverse micelles. The surfactant-laccase complex showed little activity towards the oxidative reaction of bisphenol A in water-saturated isooctane (i.e., 0.0055% [v/v] water) while effectively catalyzed the same reaction in isooctane containing 4% (v/v) water, which is over the maximum water solubility. The latter system was homogeneous and was only achieved by the aid of reverse micelles. With respect to the oxidation of bisphenol A, two products, 4-isopropylphenol and 4-isopropenylphenol, were identified by gas chromatography-mass spectrometry (GC-MS) analyses, indicating the oxidative degradation of the bis-phenolic structure of bisphenol A. We also found that the surfactant-laccase complex turned out to handle other environmental pollutants, chlorophenols, by the simultaneous addition of water and a redox mediator into the reaction medium using reverse micelles.     

Solubility-normalized combined adsorption-partitioning sorption isotherms for organic pollutants

Equilibrium sorption isotherms were measured for five different low-polarity organic compounds (benzene, trichloroethene, 1,2- and 1,4-dichlorobenzene, and phenanthrene) over a wide concentration range. The investigated sorbents can be grouped into the following three classes: (1) humic soil organic matter, which shows linear sorption isotherms (solely partitioning, as observed in the peat sample); (2) carbon materials, which were thermally altered (due to their natural history or industrial production) and thus contain a high specific surface area and exhibit nonlinear isotherms, and (3) pure engineered microporous materials (e.g., zeolites and activated carbon), where adsorption is solely due to a pore-filling process. Sorption of all compounds was fitted very well by the Polanyi-Dubinin-Manes (PDM) model, which for sorbents containing humic organic matter (e.g., peat) was combined with linear partitioning. Both the partitioning and the Polanyi-Dubinin-Manes model predict unique sorption isotherms of similar compounds if the solubility-normalized aqueous concentration is used. In addition, an inverse linear relationship between the distribution coefficient (Kd) and water solubility, which was very well confirmed by the data, is obtained. This also leads to unit-equivalent Freundlich sorption isotherms and explains the often observed apparent correlation between sorption capacity at a given concentration (e.g., Freundlich coefficient) and sorption nonlinearity (Freundlich exponent).