利用聚合氯化铝铁处理电镀废水的研究

电镀废水是污染严重的废水之一,采用絮凝的方法处理电镀废水,操作简单,经济适用.合成无机高分子絮凝剂聚合氯化铝铁处理电镀废水,可降低处理成本,提高絮凝效果.探讨了pH值以及投药量对絮凝效果的影响,并与聚铁、聚铝的絮凝效果作了比较研究.结果表明,聚合氯化铝铁兼有聚合铝和聚合铁的优点,形成的絮凝体大而重,并且沉降速度快,适用的pH值范围也更广,絮凝效果较聚铁、聚铝更为优异,而且用药量少,具有明显的价格优势.     

油田腐蚀实例及腐蚀机理解析与控制技术

对赵州桥油田生产设备的腐蚀状况进行了全面的调查和事例分析，通过腐蚀介质化学成分分析和腐蚀试验初步研究了油田污水介质中碳钢的腐蚀机理，确定了其主要腐蚀因素为高含量的Cl^-和微生物的活动。室内试验和现场试验的结果表明，这些因素导致了强烈的点蚀倾向，是构成油田设备腐蚀穿孔的主要原因。基于腐蚀事例分析和腐蚀机理研究的结果，针对油田的不同生产设备和生产环境，提出并实施了相应的腐蚀控制措施。     

Batch growth kinetics of an indigenous mixed microbial culture utilizing m-cresol as the sole carbon source

An indigenous mixed microbial culture, isolated from a sewage treatment plant located in Guwahati was used to study biodegradation of m-cresol in batch shake flasks. m-Cresol concentration in the growth media was varied from 100mg/L to 900mg/L. The degradation kinetics was found to follow a three-half-order model at all initial m-cresol concentrations with regression values greater than 0.97. A maximum observed specific degradation rate of 0.585h(-1) was observed at 200mg/L m-cresol concentration in the medium. In the range of m-cresol concentrations used in the study, specific growth rate of the culture and specific degradation rates were observed to follow substrate inhibition kinetics. These two rates were fitted to kinetic models of Edward, Haldane, Luong, Han-Levenspiel, and Yano-Koga that are used to explain substrate inhibition on growth of microbial culture. Out of these models Luong and Han-Levenspiel models fitted the experimental data best with lowest root mean square error values. Biokinetic constants estimated from these two models showed good potential of the indigenous mixed culture in degrading m-cresol in wastewaters.     

基于高通量测序技术研究不同品种桃果实的微生物多样性

目的 探究贵州不同品种桃果实附着的微生物菌群组成情况。方法 以镇远红桃、镇远艳红桃和玉屏黄桃为试材,利用高通量测序技术分析贵州不同品种桃果实微生物的多样性。结果 红桃的主要优势细菌属为泛菌属、鞘氨醇单孢菌属和假单胞菌属,优势真菌属为枝孢菌属、交链孢属和曲霉属;艳红桃的优势细菌属为拟杆菌属、布老特氏菌属和甲基杆菌属,优势真菌属为链核盘菌属、枝孢菌属和交链孢属;黄桃的优势细菌属为甲基杆菌属、鞘氨醇单孢菌属和棒状杆菌属,优势真菌属为枝孢菌属、链核盘菌属和交链孢属。此外,α多样性分析表明艳红桃的真菌多样性最高,而黄桃的真菌多样性次之;β多样性分析表明构成不同品种桃群落组成有明显差异,而黄桃与红桃的群落组成相似程度更高。结论 研究初步明确了贵州不同品种桃果实的微生物多样性,为不同品种桃果实的绿色生产和贮藏保鲜提供理论基础。     

阳离子有机高分子絮凝剂的研究进展

絮凝沉淀法是广泛使用的水处理技术之一,而絮凝剂是絮凝法水处理的核心技术.与无机絮凝剂相比,有机高分子絮凝剂具有用量少、成本低、毒性小等优点,因此它的开发应用越来越受关注.而阳离子有机高分子絮凝剂由于带有可离解的阳离子更适合于水处理应用.本文介绍了阳离子聚丙烯酰胺类、天然高分子改性类、烷基烯丙基卤化铵类和环氧氯丙烷与胺反...     

Chemical warfare and survival strategies in bacterial range expansions

Dispersal of species is a fundamental ecological process in the evolution and maintenance of biodiversity. Limited control over ecological parameters has hindered progress in understanding of what enables species to colonize new areas, as well as the importance of interspecies interactions. Such control is necessary to construct reliable mathematical models of ecosystems. In our work, we studied dispersal in the context of bacterial range expansions and identified the major determinants of species coexistence for a bacterial model system of three Escherichia coli strains (toxin-producing, sensitive and resistant). Genetic engineering allowed us to tune strain growth rates and to design different ecological scenarios (cyclic and hierarchical). We found that coexistence of all strains depended on three strongly interdependent factors: composition of inoculum, relative strain growth rates and effective toxin range. Robust agreement between our experiments and a thoroughly calibrated computational model enabled us to extrapolate these intricate interdependencies in terms of phenomenological biodiversity laws. Our mathematical analysis also suggested that cyclic dominance between strains is not a prerequisite for coexistence in competitive range expansions. Instead, robust three-strain coexistence required a balance between growth rates and either a reduced initial ratio of the toxin-producing strain, or a sufficiently short toxin range.     

Carbon‐Based Microbial‐Fuel‐Cell Electrodes: From Conductive Supports to Active Catalysts

Microbial fuel cells (MFCs) have attracted considerable interest due to their potential in renewable electrical power generation using the broad diversity of biomass and organic substrates. However, the difficulties in achieving high power densities and commercially affordable electrode materials have limited their industrial applications to date. Carbon materials, which can exhibit a wide range of different morphologies and structures, usually possess physiological activity to interact with microorganisms and are therefore fast‐emerging electrode materials. As the anode, carbon materials can significantly promote interfacial microbial colonization and accelerate the formation of extracellular biofilms, which eventually promotes the electrical power density by providing a conductive microenvironment for extracellular electron transfer. As the cathode, carbon‐based materials can function as catalysts for the oxygen‐reduction reaction, showing satisfying activities and efficiencies nowadays even reaching the performance of Pt catalysts. Here, first, recent advancements on the design of carbon materials for anodes in MFCs are summarized, and the influence of structure and surface functionalization of different types of carbon materials on microorganism immobilization and electrochemical performance is elucidated. Then, synthetic strategies and structures of typical carbon‐based cathodes in MFCs are briefly presented. Furthermore, future applications of carbon‐electrode‐based MFC devices in the energy, environmental, and biological fields are discussed, and the emerging challenges in transferring them from laboratory to industrial scale are described.     

微生物源食品保鲜剂的研究进展

目的 介绍近5年微生物源食品保鲜剂的研究进展,为研究高效、无毒、天然的食品保鲜剂提供理论和方法依据.方法 综述常见的微生物源食品保鲜剂,包括细菌源保鲜剂、真菌源保鲜剂和微生物代谢产物保鲜剂(乳酸链球菌素、￡-聚赖氨酸、溶菌酶和纳他霉素).简要说明其抑菌机理和存在的问题.结果 微生物源保鲜剂可以通过竞争营养,诱导系统抗性和产生活性代谢产物等方式抑制多种致病菌的生长繁殖,降低果蔬病害的发生率,保持食品良好的感官品质和理化特性,有效延长食品货架期.结论 微生物源保鲜剂为食品保鲜贮藏提供了新途径.其抑菌机理和潜在毒性需进一步明确,如何提高微生物源保鲜剂抗不良环境的稳定性还有待进一步研究.     

Antimicrobial Activity of Parabens in Submicron Emulsions Stabilized with Lecithin

Antimicrobial efficacy of methyl and propylparaben combination as potential preservatives for submicron emulsions, and the effect of oil and lecithin concentration on the microbial growth were investigated. Parabens were ineffective in standard or doubled concentrations as per pharmacopoeial criteria. Poor growth inhibition and multiplication of reference strains point to protective and growth properties of submicron emulsions. No correlation was observed between oil/lecithin ratio and efficacy of parabens; partitioning of the latter into the oily phase and lipophilic domains could be the reason for such effect. Further studies are necessary to establish a stable and safe composition of such formulations.     

Artificial Microbial Arenas: Materials for Observing and Manipulating Microbial Consortia

From the smallest ecological niche to global scale, communities of microbial life present a major factor in system regulation and stability. As long as laboratory studies remain restricted to single or few species assemblies, however, very little is known about the interaction patterns and exogenous factors controlling the dynamics of natural microbial communities. In combination with microfluidic technologies, progress in the manufacture of functional and stimuli‐responsive materials makes artificial microbial arenas accessible. As habitats for natural or multispecies synthetic consortia, they are expected to not only enable detailed investigations, but also the training and the directed evolution of microbial communities in states of balance and disturbance, or under the effects of modulated stimuli and spontaneous response triggers. Here, a perspective on how materials research will play an essential role in generating answers to the most pertinent questions of microbial engineering is presented, and the concept of adaptive microbial arenas and possibilities for their construction from particulate microniches to 3D habitats is introduced. Materials as active and tunable components at the interface of living and nonliving matter offer exciting opportunities in this field. Beyond forming the physical horizon for microbial cultivates, they will enable dedicated intervention, training, and observation of microbial consortia.