基于MABR的压裂返排液处理及微生物群落研究

压裂返排液含有多种复杂有机物,毒性高、盐度高以及可生化性差。设计了1个三级MABR系统用于压裂返排液的处理,该系统在最适宜运行参数下表现出优异的除碳脱氮性能,出水经过芬顿试剂处理后满足污水综合排放二级标准。MABR系统对COD、NH⁺₄-N和TN的去除率分别达到79.30%、96.06%和75.61%。微生物分析表明MABR生物膜富集了丰富的功能菌群,Proteobacteria(变形菌门)、Bacteroidetes(拟杆菌门)是生物膜中的优势菌群。阐明了MABR处理压裂返排液的技术可行性,为MABR在处理相关废水中的应用奠定了基础。     

共价有机骨架材料的制备及在环境领域的应用

共价有机框架(Covalent organic frameworks,COFs)材料是一类多孔的,由共价有机结构块组成的有机高分子材料。由于COFs材料优良的性能使其在环境领域具有广泛的应用。本文对COFs材料的合成、修饰以及COFs材料及其衍生物在环境修复领域的应用进行了总结,并针对目前COFs材料在环境修复领域的研究存在的问题及未来的研究方向进行了讨论和展望。     

Bacterially Secretable Single-Chain Tandem Macrocyclic Peptides for High Affinity and Inhibitory Activity

The inhibition of protein-protein interactions (PPIs) is an effective approach for therapy. Owing to their large binding surface areas to target proteins, macrocyclic peptides are suitable molecules for PPI inhibition. In this study, we developed single-chain tandem macrocyclic peptides (STaMPtides) that inhibits the vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2). They were artificially designed to comprise two different VEGFR2-binding macrocyclic peptides linked in tandem by peptide linkers and secreted by Corynebacterium glutamicum. Most potent VEGFR2-inhibitory STaMPtides with length-optimized linkers exhibited >1000 times stronger inhibitory activity than their parental monomeric peptides, possibly due to the avidity effect of heterodimerization. Our approach of using STaMPtides for PPI inhibition may be used to inhibit other extracellular factors, such as growth factors and cytokines.     

Tetrasodium iminodisuccinate as a biodegradable complexing agent for remediating metal-contaminated soil

Soil washing is a rapid and cost-effective method to treat contaminated soils. However, conventional chelating agents exhibit adverse environmental effects. Tetrasodium iminodisuccinate (IDS) is a new type of amino carboxyl chelating agent, which exhibits strong chelating performance, high solubility in aqueous solution, and is environmentally friendly in soil. In this study, batch washing of Cu, Pb, and Cd removal from simulated contaminated soil and real project-scale soil of a Pb-polluted field was explored to evaluate the application of IDS in the remediation of potentially toxic metal-contaminated soil. The effects of the IDS solution pH, concentration, reaction temperature, liquid/soil (L/S) ratio, number of washing cycles, and contact duration were investigated, and the optimal conditions were identified as follows: pH 7, IDS concentration 10 mmol · L⁻¹, L/S ratio 10:1; 25°C; and 24 h. Almost 80.6% of Cu, 71.1% of Pb, and 59.1% of Cd were removed from simulated contaminated soil under optimal conditions. The primary potentially toxic metal removal mechanisms were analyzed by potentially toxic metal state detection before and after IDS washing. Real project-scale Pb-polluted field washing was demonstrated under the same conditions in addition to the IDS concentration of 4.5 mmol · L⁻¹. The Pb concentration was reduced from 460 to 86.8 mg · kg⁻¹ (mean value), which is below the threshold identified in the ‘Risk Assessment of Soil Environmental Health in Shanghai’ (Residential Area, 140 mg · kg⁻¹). The results confirm that IDS is a promising soil washing agent that can effectively remove potentially toxic metals from contaminated soil and minimize environmental risks.     

Use of surfactants and blends to remove DDT from contaminated soils

Removal of dichloro‐diphenyl‐trichloroethane (DDT) from soils using surfactant‐enhanced solubilisation was studied both in batch and continuous flow arrangements to determine if there were advantages to using a combination of non‐ionic (Tween and Brij) and anionic surfactants. It was observed that the presence of the anionic surfactant sodium dodecyl benzene sulphonate improved the DDT removal efficiency, but had a potentially negative effect on flow rates in column leaching experiments at concentrations over 0.1%. The potential for re‐use of the surfactant mixture was studied and demonstrated by removing DDT and its metabolites from the surfactant solution using activated carbon. © 2011 Canadian Society for Chemical Engineering     

Editorial of the Special Issue Antimicrobial Polymers

The special issue “Antimicrobial Polymers” includes research and review papers concerning the recent advances on preparation of antimicrobial polymers and their relevance to industrial settings and biomedical field. Antimicrobial polymers have recently emerged as promising candidates to fight microbial contamination onto surfaces thanks to their interesting properties. In this special issue, the main strategies pursued for developing antimicrobial polymers, including polymer impregnation with antimicrobial agents or synthesis of polymers bearing antimicrobial moieties, were discussed. The future application of these polymers either in industrial or healthcare settings could result in an extremely positive impact not only at the economic level but also for the improvement of quality of life.     

β-Cyclodextrin Inclusion Complex to Improve Physicochemical Properties of Pipemidic Acid: Characterization and Bioactivity Evaluation

The aptitude of cyclodextrins (CDs) to form host-guest complexes has prompted an increase in the development of new drug formulations. In this study, the inclusion complexes of pipemidic acid (HPPA), a therapeutic agent for urinary tract infections, with native β-CD were prepared in solid state by kneading method and confirmed by FT-IR and ¹H NMR. The inclusion complex formation was also characterized in aqueous solution at different pH via UV-Vis titration and phase solubility studies obtaining the stability constant. The 1:1 stoichiometry was established by a Job plot and the inclusion mechanism was clarified using docking experiments. Finally, the antibacterial activity of HPPA and its inclusion complex was tested on P. aeruginosa, E. coli and S. aureus to determine the respective EC_50s and EC_90s. The results showed that the antibacterial activity of HPPA:β-CD against E. coli and S. aureus is higher than that of HPPA. Furthermore, HPPA and HPPA:β-CD, tested on human hepatoblastoma HepG2 and MCF-7 cell lines by MTT assay, exhibited, for the first time, antitumor activities, and the complex revealed a higher activity than that of HPPA. The use of β-CD allows an increase in the aqueous solubility of the drug, its bioavailability and then its bioactivity.     

絮凝剂产生菌的研究新进展

微生物絮凝剂有着广阔的应用前景,絮凝剂产生菌的研究成为人们关注的焦点。讨论了絮凝剂产生菌的研究概况、菌种筛选方法和培养条件等,且就今后的研究提出了某些建议。     

添加羟胺诱导Streptomyces hygroscopicus产谷氨酰胺转胺酶

研究了添加羟胺对Streptomyces hygroscopicus合成谷氨酰胺转胺酶的影响. 结果表明,添加羟胺可诱导谷氨酰胺转胺酶的合成. 摇瓶培养过程中,羟胺的最适添加量和最适添加时间分别为0.5 mmol/L和38 h,发酵结束时,谷氨酰胺转胺酶酶活最高达到5.3 U/mL,比对照提高了32.5%. 添加羟胺可诱导Streptomyces hygroscopicus产酶,羟胺与谷氨酰胺转胺酶反应的结果是产生了L-谷氨酸-g-单羟肟酸,实验证明它对Streptomyces hygroscopicus产酶有抑制作用. 诱导产酶过程是羟胺的促进作用和L-谷氨酸-g-单羟肟酸的抑制作用逐步达到平衡、最后酶活趋于稳定的过程.