Combination of levulinic acid and sodium dodecyl sulfate on inactivation of foodborne microorganisms: A review

Abstract

The combination of levulinic acid and sodium dodecyl sulfate (SDS) in recent years has shown considerable promise as an antimicrobial intervention. Both ingredients have been designated by the U.S. Food and Drug Administration (FDA) as Generally Recognized as Safe (GRAS) for being used as a flavoring agent and multipurpose food additive, respectively. The use of levulinic acid and SDS alone has limited antimicrobial efficacy on tested microorganisms, and synergism between levulinic acid and SDS has been observed. The postulated mechanism of action of the synergistic effect is presented. The antimicrobial efficacy of levulinic acid plus SDS remains high even when organic materials are present. The other features, including penetration, foamability, and being readily soluble, extend its potential applications to disinfection of difficult-to-access areas and control of foodborne pathogens both in a planktonic state and in a biofilm. These features indicate that the levulinic acid plus SDS combination may have the potential to be applied within the food processing environment on a large scale.     

加料方式对Cu-Co合成低碳醇催化剂性能的影响

低碳醇在汽油添加剂或汽油替代品减少尾气排放等方面具有潜在用途,用煤和天然气经合成气合成低碳醇的Cu-Co催化剂在较为缓和条件下具有较高的催化活性和C₂+OH醇选择性。采用不同沉淀方法制备系列Cu-Co催化剂,通过XRD、XPS、TPR和BET考察加料方式对催化剂前驱体和催化剂性能的影响。在5.0 MPa、250 ℃和空速5 000 h^-1条件下,使用加压固定床反应器考察合成低碳醇活性。研究结果表明,加料方式对催化剂性能有较大影响,采用共沉淀法制备的催化剂颗粒中各组分以纳米大小均匀分布,C₂+OH醇选择性最高;采用正加法制备的催化剂活性和C₂+OH醇选择性最低,催化剂颗粒中活性组分的分布呈壳层分布,Co在颗粒的表面富集;采用并流法和反加法制备的催化剂的醇分布遵从ASF规则,其链增长因子为0.42。实验结果表明,当Cu和Co在催化剂颗粒中以原子尺度分布时,催化活性最好。     

Bioaugmentation of floating treatment wetlands for the remediation of textile effluent

This pilot study evaluated the effects of bacterial augmentation on the efficiency of floating treatment wetlands (FTWs) to remediate textile wastewater. Two wetland plants, Phragmites australis and Typha domingensis, were used to develop FTWs, which were then augmented with a bacterial consortium of three strains (Acinetobacter junii, Pseudomonas indoloxydans, and Rhodococcus sp.). Results showed that both plant species removed colour, organic matter, toxicity, and heavy metals from textile wastewater and their removal efficiency was further enhanced by augmentation with bacteria. The maximum removal efficiencies of colour, COD and BOD after an 8‐day period were 97, 87 and 92%, respectively, by FTWs carrying P. australis inoculated with the bacterial consortium. Furthermore, the same combination showed 87–99% reduction of heavy metals in the textile wastewater as well. These results indicate that FTWs can be used for the treatment of textile effluent and their working efficiency can be improved by plant‐bacterial synergism.     

380g/L噁草酮悬浮剂及其不同桶混助剂配伍室内防除稻田杂草活性试验

温室盆栽法测定除草活性试验结果表明,380g/L噁草酮悬浮剂及其不同桶混助剂配伍对水稻稗草有较好的除草活性,特别是加入桶混助剂GY—Hba S2#的380g/L噁草酮悬浮剂在试验中产生较显著的增效作用。     

工业锅炉烟气多污染物排放协同净化技术综述

介绍了国内外工业锅炉烟气多污染物协同净化技术现状,包括基于液相催化氧化法等传统协同技术、LJD循环流化床法等新协同技术的原理、特征和改进方向,并对国内外发展的烟气多污染物净化技术的原理及研究现状进行评述,对比了各种技术的性能,展望了工业锅炉多污染物净化技术的发展前景与技术方向。     

基于协同学理论的虚拟企业合作伙伴选择研究

为最大化虚拟企业项目中各任务间的协同程度,提出了一种基于协同学理论的虚拟企业伙伴选择方法。建立了以极大化系统协同度为优化目标的伙伴选择模型,该模型考虑了系统的交货时间、总费用和产品准时交货率等因素的协同度。此外,针对基本杂草算法在求解伙伴选择模型的过程中容易陷入局部极值的缺点,设计了一种嵌入混沌搜索行为的混合杂草算法来求解该模型。仿真结果表明了该方法的可行性及有效性。     

微波-超声波协同影响菜籽蛋白糖基化改性

采用微波-超声波协同作用强化菜籽蛋白的糖基化改性,并对所得糖基化产物进行了功能性质和分子结构的对比分析。结果表明,当改性条件为微波功率500 W、超声波功率300 W、协同作用时间7 min时,菜籽蛋白的接枝度可达67.1%,显著高于湿热法和微波法制备的糖基化产物,有效提高了蛋白质糖基化反应的效率;协同作用可显著改善所得糖基化产物的溶解性、乳化活性、起泡能力、泡沫稳定性,分别提高至55.7%、13.9 m~2/g、50.0%和80.0%;糖基化产物的表面疏水性和圆二色谱结果分析表明,微波和超声波处理使得菜籽蛋白的分子展开,表面疏水性和分子柔性增加,从而促进了糖基化反应的进行,改善了蛋白质糖基化产物的功能特性。     

DSD酸-三嗪类荧光增白剂的复配与增效

本文简介了复配型荧光增白剂的概念、复配的种类和方法、复配型荧光增白剂能产生加和增效的原理。介绍了国内DSD酸-三嗪类复配型荧光增白剂的研究和生产概况并列举了几项研究成果在实际应用中的效果。     

Barrier effect of flame retardant systems in poly(methyl methacrylate): Study of the efficiency of the surface treatment by octylsilane of silica nanoparticles in combination with phosphorous fire retardant additives

In this work, flame retardant systems comprising ammonium polyphosphate (AP423) and hydrophilic (A200) or hydrophobic (R805) nanometric silica were incorporated into PMMA. The following techniques were performed to detail the fire behaviour of the composites: mass loss cone calorimetry, pyrolysis‐combustion flow calorimetry, pyrolysis‐gas chromatography–mass spectrometry, thermogravimetric analysis, X‐ray diffraction analysis, Fourier transform infrared spectroscopy and microscopic observations. The best fire behaviour was obtained with the surface‐treated silica in the presence of AP423. The formation of a new crystalline phase from the interactions between AP423 and R805 silica and a strong barrier effect due to a layered residue were the main modes of action of this system. Moreover, we have shown that the difference between the AP423 + R805 and AP423 + A200 systems was due to poor dispersion of the silica into the PMMA matrix in the latter formulation. Copyright © 2011 John Wiley & Sons, Ltd.     

Enhancing saccharification of Agave tequilana bagasse by oxidative delignification and enzymatic synergism for the production of hydrogen and methane

Agave tequilana bagasse is a suitable lignocellulosic residue for energy production. However, the presence of lignin and the heterogeneous structure of hemicellulose may hinder the availability of polysaccharides. In this work, the pretreatment of A. tequilana bagasse with alkaline hydrogen peroxide (AHP) followed by enzymatic saccharification with hemicellulases and cellulases was assessed for the removal of lignin and extraction of fermentable sugars, respectively. Results of the AHP pretreatment indicated that it is possible to attain up to 97% delignification and recover 88% of cellulose and hemicellulose after only 1.5 h of treatment. Regarding the saccharification process, the total sugar yield and productivity were both increased by 2-fold using an enzymatic mixture (cellulases + hemicellulases) compared to single enzyme hydrolysis (cellulases), evidencing synergism. Further evaluation of the hydrolyzates as substrate for hydrogen and methane production, resulted in yields 1.5 and 3.6-times (215.14 ± 13 L H₂ and 393.4 ± 13 L CH₄ per kg bagasse, respectively) superior to those obtained with hydrolyzates of non-pretreated bagasse processed with a single enzyme. Overall, using AHP pretreatment and subsequent hydrolysis with enzymatic mixtures improves the saccharification of A. tequilana bagasse enhancing the production of hydrogen and methane.