固定化微生物处理氨氮废水的研究进展

生物方法因其高效、持久及无二次污染已经成为治理水污染的重要方法,固定化微生物不仅加强微生物治理效果,更能保证微生物生存稳定,是现阶段生物方法治理水污染的主要组分。近年来学者们也做了很多固定化微生物处理各类废水的研究,并取得了大量优异成果。文章对固定化微生物技术进行剖析,分析各类固定化载体材料及各种固定化方法优缺点;解析利用固定化微生物处理氨氮废水效果研究及固定化微生物处理效果影响因素;综述近年来固定化微生物处理氨氮废水应用情况;最后进行总结,并提出自己的展望。     

微生物固定化技术在水体修复中的研究进展

微生物固定化技术目前已被广泛应用于环境生态修复等领域,对此,文章围绕微生物固定化技术,基于前人的研究成果和目前微生物固定化技术的相关研究进展,及其在水体修复方面的应用展开了探讨,并提出了发展展望,期望能够为微生物固定化技术的发展应用提供有益参考。     

超高压处理对微生物生理特性的影响

单核增生李斯特菌(Listeriamonocytogenes)NCTC11994和大肠杆菌(Escherichiacoli)ATCC80739经高压处理,其生理特性发生了深刻的变化,主要表现是400MPa以上的压力处理10min,微生物数量下降7个对数单位,压力处理还会导致细胞内pH值的变化,使膜电位下降,细胞内钾流失,ATP浓度降低。     

纳米材料固定化酶的研究进展

近年来,纳米技术为酶固定化提供了多种纳米级材料,纳米材料固定化酶不仅具有高的酶负载量,而且具有良好的酶稳定性。本文基于纳米材料固定化酶,对纳米材料的种类进行了总结,分析了纳米材料对固定化酶性能的影响,并介绍了纳米级固定化方法及纳米材料固定化酶在生物转化、生物传感器、生物燃料电池等领域的应用。     

竹炭固定化微生物对水中壬基酚的降解效率

竹炭是一种优质生物质炭,不仅比表面积大,孔隙发达,而且机械强度高,是微生物固定化载体的最佳选择之一.本文采用正交试验确定了竹炭固定化微生物的最佳制备条件,对比了竹炭固定菌和游离菌对水中类雌激素壬基酚的降解效果,并考察了竹炭固定菌的重复利用性.结果表明:固定化后降解菌大量地附着在竹炭表面及内部孔隙中,其最佳制备条件为温度30℃、pH=7、竹炭粒径35目.壬基酚的降解符合一级动力学方程,在不同的壬基酚初始浓度下(30、50、80、100 mg·L^-1),竹炭固定菌对壬基酚的7 d降解率分别为100%、75.3%、67.3%和78.7%,显著优于游离菌(54.2%、51.5%、30.6%和23.5%).经过8轮重复利用后,竹炭固定菌对壬基酚的降解率仍可达到36.5%,而此时游离菌的降解率仅为8.9%,说明竹炭固定菌具有长期可重复利用性,在去除废水有机污染物中具有较好的工程应用前景.     

聚乙烯醇包埋固定化微生物的研究及进展

对聚乙烯醇包埋固定化微生物的原理,固定化方法的改进以及固定化细胞的应用进行了综述,ＰＶＡ是一种廉价的包埋材料,具有实用价值。     

微生物固定化及其在环境污染治理中的应用研究进展

微生物固定化技术广泛应用于食品、轻化以及环保领域,其具有微生物密度高、生物活性好、环境适应性强、可反复利用等优点。本文对微生物固定化技术进行了概述,并通过典型案例重点阐释了其在水、土和大气等环境污染治理领域的应用进展。在水环境中,固定化载体可为不同类型微生物提供生存微环境和各自所需的生态位,提高了系统负荷和处理效能;在土壤环境中,其重要作用在于提高土壤中污染物的生物有效性,从而提升微生物修复效果;空气污染治理领域则更注重载体的机械强度及气液传质能力的提高。本文比较总结了微生物固定化技术在不同环境治理领域中的应用特点和优势,以期为今后的环境污染治理提供一定的参考。     

无花果蛋白酶在阴离子交换树脂上的固定化

无花果蛋白酶通过８％戊二醛活化载体,共价结合到聚苯乙烯阴离子交换树脂ＧＭ２０１上,固定化作用在ｐＨ７．７,酶浓度０．８ｍｇ／ｇ树脂,４℃下进行６ｈ。得到的固定化酶表观Ｋ_ｍ值（酪蛋白,１．１１×１０~（－４）ｍｏｌ／Ｌ）小于溶液酶Ｋ_ｍ值（１．９６×１０~（－４）ｍｏｌ／Ｌ）;固定化酶活性在ｐＨ６～８保持稳定,溶液酶最适ｐＨ为７．２;固定化酶最适温度由溶液酶的５０～６０℃移至３７℃;固定化酶２５℃保持７ｄ,重复水解酪蛋白７次后,保留８３．３％活性。固定化酶对酪蛋白水解度达４７．５％,对大豆球蛋白达１１．６％。     

Immobilization of Candida cylindracea lipase on poly lactic acid,polyvinyl alcohol and chitosan based ternary blend film: Characterization,activity, stability and its application for N-acylation reactions

The ecofriendly ternary blend polymer film was prepared from the chitosan (CH), polylactic acid (PLA) and polyvinyl alcohol (PVA). Immobilization of Candida cylindracea lipase (CCL) was carried out on ternary blend polymer via entrapment methodology. The ternary blend polymer and immobilized biocatalyst were characterized by using N₂ adsorption–desorption isotherm, SEM, FTIR, DSC, and (%) water content analysis through Karl Fischer technique. Biocatalyst was then subjected for the determination of practical immobilization yield, protein loading and specific activity. Immobilized biocatalyst was further applied for the determination of biocatalytic activity for N-acylation reactions. Various reaction parameters were studied such as effect of immobilization support (ratio of PLA:PVA:CH), molar ratio (dibutylamine:vinyl acetate), solvent, biocatalyst loading, time, temperature, and orbital speed rotation. The developed protocol was then applied for the N-acylation reactions to synthesize several industrially important acetamides with excellent yields. Interestingly, immobilized lipase showed fivefold higher catalytic activity and better thermal stability than the crude extract lipase CCL. Furthermore various kinetic and thermodynamic parameters were studied and the biocatalyst was efficiently recycled for four successive reuses. It is noteworthy to mention that immobilized biocatalyst was stable for period of 300 days.     

生物脱硫中氧化亚铁硫杆菌固定化技术的研究

在生物脱硫过程中,以焦碳为填料作为固定化载体,进行了氧化亚硫杆菌的固定化技术研究。在初始pH2、温度为30℃左右、通气量0.5m3/h、喷淋量1.0L/h条件下,挂膜后只需12h,Fe2 氧化率可达95.28%,其Fe2 平均氧化速率是游离细胞时的8倍。氧化亚铁硫杆菌固定化细胞经长期低pH值驯化后,仍能保持对Fe2 具有较高的氧化活性;只需20hFe2 氧化率就达95.05%,Fe2 平均氧化速率达0.38g/(L/h)。     

NAD+ regeneration in a microreactor using permeabilized baker’s yeast cells

NAD(P)-dependent oxidoreductases represent a great interest in the field of biotechnology and biotransformation. Although they have many advantages, the biggest drawback and limitation of oxidoreductase usage is the price of the coenzymes. In order to solve this problem, many in situ methods for regeneration of coenzymes have been studied and developed. Unfortunately, although results indicate that those methods are suitable for regeneration procedure, most of the processes need additional optimization to make them more sustainable. As an alternative, microreactor technology could be used as a new technique for coenzyme regeneration processes due to many advantages.In this study regeneration of coenzyme NAD⁺ was carried out in a microreactor by acetaldehyde reduction to ethanol using enzyme alcohol dehydrogenase (ADH). Suspended and immobilized whole permeabilized baker’s yeast cells were used as the source of the ADH enzyme. A 65.3% conversion of NADH was achieved with suspended permeabilized baker’s yeast cells for a residence time of τ = 36 s and equimolar concentration of substrates (c_i,NADH = 5.5 mmol/dm³, c_{i,acetaldehyde} = 5.5 mmol/dm³). When working with immobilized cells, conversion achieved for the same residence time was 10 fold lower. When permeabilized baker’s yeast cells were used for coenzyme regeneration process was stabile for 6 days of continuous operation which makes this system a good alternative for coenzyme regeneration.     

抗体固定化方法研究进展

在免疫分析和生物芯片中,抗原-抗体特异性结合被广泛应用,其中抗体的固定化是研发高效诊断和分离工具的关键环节。生物分子工程、材料化学与交联剂化学的进步极大地促进了抗体固定化技术的发展。 抗体可以通过物理吸附、共价偶联和亲和相互作用固定到不同类型的固相表面。 抗体固定化的目标是以一种正确的空间取向将抗体固定到固相表面,在完全保留抗体构象和活性的同时最大化抗原的结合能力,这对固相化抗体的分析性能至关重要。 对固定抗体到固相载体表面的各种最新方法进行了阐述,包括物理吸附法,通过羧基、氨基、巯基、糖基和点击化学的共价结合法以及基于生物亲和作用的固定法,并对固定化抗体的表征方法进行了归纳,最后对抗体固定化方法的发展方向进行了展望。     

Microbial carboxyl esterases: classification,properties and application in biocatalysis

Esterases (EC 3.1.1.x) represent a diverse group of hydrolases catalyzing the cleavage and formation of ester bonds and are widely distributed in animals, plants and microorganisms. Beside lipases, a considerable number of microbial carboxyl esterases have also been discovered and overexpressed. This review summarizes their properties and classification. Special emphasis is given on their application in organic synthesis for the resolution of racemates and prostereogenic compounds. In addition, recent results for altering their properties by directed evolution are presented.     

果胶酶的固定化研究

本文研究了以重氮化的对—氨基苯磺酰乙基纤维素为载体制各固定化果胶酶的最适条件,并比较了固定化果胶酶与游离酶的性质。结果表明,最适的固定化果胶酶的条件是：在ｐＨ７．００．１５Ｍ的磷酸盐缓冲液中,按每克载体加入２１６３活力单位的酶的比例进行偶联反应１２小时。在以上最适条件下,固定化果胶酶的表观活力为１９８０Ｕ／ｇ,活力回收率为８７％。与游离酶相比,固定化果过酶作用的最适ｐＨ由４．６移至４．２,最适温度变宽,酶的热稳定性增强,操作稳定性良好,半衰期为３２．５天。     

Microbial corrosion monitoring by an amperometric microbial biosensor developed using whole cell of Pseudomonas sp.

A microbial biosensor was developed for monitoring microbiologically influenced corrosion (MIC) of metallic materials in industrial systems. The Pseudomonas sp. isolated from corroded metal surface was immobilized on acetylcellulose membrane and its respiratory activity was estimated by measuring oxygen consumption. The microbial biosensor was used for the measurement of sulfuric acid in a batch culture medium contaminated by microorganisms. A linear relationship between the microbial sensor response and the concentration of sulfuric acid was observed. The response time of biosensor was 5 min and was dependent on the immobilized cell loading of Pseudomonas sp., pH, temperature and corrosive environments. The microbial biosensor response was stable, reproducible and specific for sensing of sulfur oxidizing bacterial activity.