The biofilm characteristics and enhanced performance of a marine microbial-electrolysis-cell-based biosensor under positive anodic potential

Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,two identical microbial electrolysis cell(MEC)based biosensors were inoculated with marine sediment and operated at two different anodic potentials,namely-300 mV and+250 mV relative to Ag/AgCl.The MEC biosensor operated under positive anodic potential conditions had electrochemically active microbial communities on the anode,including members of the Shewanellaceae,Pseudoalteromonadaceae,and Clostridiaceae families.However,the strictly anaerobic members of the Desulfuromonadaceae,Desulfobulbaceae and Desulfobacteraceae families were found only in the negative anodic potential MEC biosensor.The positive anodic potential MEC biosensor showed several other advantages as well,such as faster start-up,significantly higher maximum current production,fivefold improvement in the AOC detection limit,and tolerance of low dissolved oxygen,compared to those obtained from the negative anodic potential MEC biosensor.The developed positive anodic potential MEC biosensor can thus be used as a real-time and inexpensive detector of AOC concentrations in high saline and low DO seawater.

Recent progress in microbial cell surface display systems and their application on biosensors

Microbial cell surface display technology is a recombinant technology to express target proteins on the cell membrane,which can be used to redesign the cell surface with functional proteins and peptides.Bacterial and yeast surface display systems are the most common cell surface display systems of prokaryotic and eukaryotic proteins,that are widely applied as the core elements in the field of biosensors due to their advantages,including enhanced stability,high yield,good safety,expression of larger and more complex proteins.To further promote the performance of biosensors,the biomineralized microbial surface display technology was proposed.This review summarized the different microbial surface display systems and the biomineralized surface display systems,where the mechanisms of surface display and biomineralization were introduced.Then we described the recent progress of their applications on biosensors for different types of detection targets.Finally,the outlooks and tendencies were discussed and forecasted with the expectation to provide some general functions and enlightenments to this aspect of research.

Technology and Applications of Microbial Biosensor

A microbial biosensor is an analytical device that immobilizes microorganisms onto a transducer for the detection of target analytes. With the development of nanotechnology, nanomaterials have been used to achieve better immobilization for developing a more reliable and selective microbial biosensor. Also, significant progress has been made in the development of transducer technology leading to higher sensitivity. Microbial biosensors have become one of the most useful means of monitoring environmental, food and clinical samples. In this review, we focus on the newly developed technologies and applications of microbial biosensors in recent years.

生物传感器在食品微生物污染检测中的应用

微生物污染是影响食品安全的主要因素之一。传统的微生物检测方法耗时长、灵敏度低,已不能满足现代食品安全检测的需求。生物传感器具有检测速度快、灵敏度高、特异性强等优点,在食品微生物污染检测中展现出巨大的应用潜力。本文简要介绍生物传感器的种类、检测原理、性能特点及其在食品微生物污染检测中的应用,并概括生物传感器在食品微生物污染检测中的应用优势,为推广应用生物传感器、保证食品安全提供理论依据。

生物传感器技术在食品安全检测中的应用研究

生物传感器技术具有灵敏度高、检测速度快和操作简便等特点,可应用于食品安全检测领域。本文介绍了生物传感器技术的基本原理及其在微生物污染、农药残留、重金属离子和过敏原检测等方面的具体应用,并分析了该技术的优势和局限性,以期为扩大生物传感器技术在食品安全检测中的应用范围提供参考。

Improvement of a highly sensitive and specific whole-cell biosensor by adding a positive feedback amplifier

In this study,we designed a Cd^(2+)whole-cell biosensor with both positive and negative feedback cascade am-plifiers in Pseudomonas putida KT2440(LTCM)based on our previous design with only a negative feedback amplifier(TCM).The results showed that the newly developed biosensor LTCM was greatly improved compared to TCM.Firstly,the linear response range of LTCM was expanded while the maximum linear response range was raised from 0.05 to 0.1μM.Meanwhile,adding a positive feedback amplifier further increased the fluorescence output signal of LTCM 1.11–2.64 times under the same culture conditions.Moreover,the response time of LTCM for detection of practical samples was reduced from 6 to 4 h.At the same time,LTCM still retained very high sensitivity and specificity,while its lowest detection limit was 0.1 nM Cd^(2+)and the specificity was 23.29(compared to 0.1 nM and 17.55 in TCM,respectively).In summary,the positive and negative feedback cascade amplifiers effectively improved the performance of the biosensor LTCM,resulting in a greater linear response range,higher output signal intensity,and shorter response time than TCM while retaining comparable sensitivity and specificity,indicating better potential for practical applications.

Toxicity assessment of heavy metals and organic compounds using CellSense biosensor with E.coli

A new strategy using an arnperometric biosensor with Escherichia coli （E. coli） that provides a rapid toxicity determination of chemical compounds is described. The CellSense biosensor system comprises a biological component immobilized in intimate contact with a transducer which converts the biochemical signal into a quantifiable electrical signal. Toxicity assessment of heavy metals using E.coli biosensors could be finished within 30 min and the 50% effective concentrations （ECso） values of four heavy metals were determined. The results shows that inhibitory effects of four heavy metals to E.coli can be ranked in a decreasing order of Hg^2＋ 〉 Cu^2＋ 〉 Zn^2＋ 〉 Ni^2＋, which accords to the results of conventional bacterial counting method. The toxicity test of organic compounds by using CellSense biosensor was also demonstrated. The CellSense biosensor with E. coli shows a good, reproducible behavior and can be used for reproducible measurements.

微生物传感器在食品分析中的应用

微生物传感器是以活体微生物细胞为感应元件,感应需要测定的靶标物质浓度并按照一定规律转换为可识别信号的检测装置。早期的微生物传感器以微生物测定和微生物电极的形式出现,近年来随着分子生物学和合成生物学技术的进步,基因工程类微生物传感器迅速发展,并且由于其成本低、使用便捷、功能扩展性强等优势,使其在食品安全领域具有良好的应用潜力。本文介绍了微生物传感器的发展历程和基本原理,总结了微生物传感器在食品安全检测、食品品质分析、食品安全毒性评估、食品污染脱毒等方面的最新研究成果,分析了微生物传感器发展趋势和当前的技术瓶颈。本综述可为食品安全快速检测技术研究和应用人员提供信息和技术参考,推动微生物传感器领域的进一步发展。

Biosensor for maltose quantification and estimation of maltase activity

Abstract: The aim of this study was to create a laboratory model of an amperometric microbial biosensor for maltose quantification in the presence and absence of starch and to estimate the use of the model in the study of maltase activity of the culture-receptor. The biosensor for maltose was developed on the basis of a Clark-type oxygen electrode, coupled with a bioreceptor, which contained bacterial cells immobilized on the membrane. The determination of maltose concentration was based on measuring the rate of electrode current change in response to addition of the analyte. The detection limit of the biosensor was 1 μM maltose, a linear interval of standard curve was observed from 14 μM up to 1.9 mM of maltose. The microbial biosensor demonstrated good sensitivity to maltose, 36.02 nA (M-s)-1. Combination of bioreceptors on the basis of fungus and bacterium allowed of using the biosensor for quantification of maltose in the presence of starch. Changes in metabolism of the culture-receptor had an effect on the biosensor response. It indicated that the developed model was a tool of simple construction and easy-to-use in the study of maltase activity of the immobilized culture-receptor.

乳及乳制品危害因素及其检测技术研究进展

乳及乳制品中各种化学、生物及物理性危害因素一直影响乳品行业的稳定发展。针对乳及乳制品中各种危害因素,目前已开发了包括微生物检测技术、仪器分析技术、免疫分析技术和生物传感技术在内的各种检测技术。本文介绍了目前国内外乳及乳制品中的各类危害因素及其对人体健康安全所造成的影响,结合对应乳及乳制品质量安全检测技术进行分析与对比,深度解析乳及乳制品质量安全检测技术的发展进程,形成了以高通量、高灵敏度、快速化以及微型化发展的趋势,旨在为乳中危害因素的相关检测技术的发展提供借鉴参考。

Real-Time Monitoring of Dynamic Chemical Processes in Microbial Metabolism with Optical Sensors

Monitoring microbial metabolism is vital for revealing the mechanism of disease related to microbial metabolism and providing guidance for biomanufacturing processes optimization.However,it remains a grand challenge to offer real-time insights into microbial metabolism owing to the complex and dynamic process.In this paper,the recent advances and prospects of optical biosensors including the organic,genetic coding and inorganic optical biosensors are briefly described for real-time monitoring of dynamic microbial metabolism.This paper points out that challenges remain in microbial heterogeneity.We believe that this work will inspire the application of developing new methods for single cell real-time analysis.

Construction of WCB-11:A novel phiYFP arsenic-resistant whole-cell biosensor

The prediction and assessment of environmental pollution by arsenic are important preconditions of advocating environmental protection and human health risk assessment. A yellow fluorescent protein-based whole-cell biosensor for the detection of arsenite and arsenate was constructed and tested. An arsenic-resistant promoter and the regulatory gene arsR were obtained by PCR from the genome ofEscherichia coli DH5ct, andphiYFP was introduced into E. coli DH5ct as a reporter gene to construct an arsenic-resistant whole-cell biosensor （WCB-11） in which phiYFP was expressed well for the first time. Experimental results demonstrated that the biosensor has a good response to arsenic and the expression ofphiYFP. When strain WCB-11 was exposed to As^3＋ and As^5＋, the expression of yellow fluorescence was time-dependent and dose-dependent. This engineered construct is expected to become established as an inexpensive and convenient method for the detection of arsenic in the field.

Development of a whole-cell biosensor based on an ArsR-Pars regulatory circuit from Geobacter sulfurreducens

In this study,an Escherichia coli(E.coli)whole-cell biosensor for the specific detection of bioavailable arsenic was developed by placing a green fluorescent protein(GFP)reporter gene under the control of the ArsR1(GSU2952)regulatory circuit from Geobacter sulfurreducens.E.coli cells only emitted green fluorescence in the presence of arsenite and were more sensitive to arsenite when they were grown in M9 supplemented medium compared to LB medium.Under optimal test conditions,the Geobacter arsR1 promoter had a detection limit of 0.01 mM arsenite and the GFP expression was linear within a range of 0.03-0.1 mM(2.25-7.5 mg/l).These values were well below World Health Organization’s drinking water quality standard,which is 10 mg/l.The feasibility of using this whole-cell biosensor to detect arsenic in water samples,such as arsenic polluted tap water and landfill leachate was verified.The biosensor was determined to be just as sensitive as atomic fluorescence spectrometry.This study examines the potential applications of biosensors constructed with Geobacter ArsR-Pars regulatory circuits and provides a rapid and cost-effective tool that can be used for arsenic detection in water samples.

Construction of a dual fluorescence whole-cell biosensor to detect N-acyl homoserine lactones

Detection of N-acyl homoserine lactones （AHLs） is useful for understanding quorum sensing （QS） behaviors, including biofilm formation, virulence and metabolism. For detecting AHLs and indicating the host cells in situ, we constructed the plasmid pUCGMA2T1-4 to make a dual fluorescent whole- cell biosensor based on the AhlI/R AHL system of Pseudomonas syringae pv. syringae B728a. The plasmid contains three components： constitutively expressed enptll：：gfP for indicating host cells, Pahll：：mcherry that produces red fluorescence in response to AHL, and the ahIR gene that encodes an AHL regulatory protein. Meanwhile, two copies of T1-4 （four tandem copies of a transcriptional terminator） were added into the plasmid to reduce background. The results showed that when the plasmid was placed into Escherichia coli, the dual fluorescence whole-cell biosensor was able to respond with red fluorescence within 6 hr to 5 × 10^-8-1 × 10^-5 mol/L of 3OC6-HSL. Bright green fluorescence indicated the host cells. Furthermore, when the plasmid was transferred to wild- type Pseudomonas PhTA125 （an AHL-producing bacterium）, it also showed both green and red fluorescence. This result demonstrates that this plasmid can be used to construct whole-cell indicators that can indicate the AHL response and spatial behaviors of microbes in a mi tal niche

New application of microbial fuel cell-based biosensor for monitoring the quality of actual potato chips’processing wastewater

In this study,a dual-chamber microbial fuel cell(MFC)fed with actual potato chips’processing wastewater(PCPW)was tested as a biosensor.The performance of MFC-based biosensor was evaluated in terms of the current measurement range,toxicity detection and sensitivity,and the operational stability.The results revealed that the MFC can simply be converted to an online biosensor unit to detect the harmful effect of suspended solids and acidic content in the actual PCPW on the anodic attached biofilm and the values of the generated current as well.A notable decrease in the current values was observed indicating the adverse effects of the harmful matters in the PCPW fed to the biosensor unit.The results proposed a competition between the harmful components and the favorable substrate in binding to the redox complex.An excellent fitting was obtained between the experimental and predicted results by I_(Km) model with determination coefficient(R^(2))and mean-square-error values of 0.927 and 0.363,respectively.Additionally,a new approach was developed based on direct measurement of actual field data to replace the conventional statistical methods.

微生物传感器研究进展

对微生物传感器结构、功能及其在环境监测、生物工程、医学等领域的最新应用进行了综合评述,探讨了微生物固定化方法对传感器性能的影响,并对微生物传感器研究进展和应用前景进行了分析展望。

微生物燃料电池的研究应用进展

微生物燃料电池是利用微生物作为催化剂,氧化分解生物质同时输出电能的一种新装置,因其可将生物质中化学能直接转化为电能,可获得更高的能量转化效率,是未来缓解能源和环境问题的有效途径,引起了科研工作者的广泛关注。本文结合近几年微生物燃料电池的发展,综述了产电微生物种类、电池材料及其改性、反应器的放大以及微生物燃料电池应用方面的研究进展,分析了该领域未来发展的主要方向及面临的问题,指出筛选和诱导产电菌对不同有机底物的耐受性,开发高效价廉的电极材料以及构建易于放大的电池模式,是微生物燃料电池未来研究的重点。在此基础上,应该着重于反应器放大,深入研究其在废水处理、产氢、微生物电化学合成以及传感器方面的应用,确定其实际应用的相关参数和模型,为微生物燃料电池早日实际应用打下坚实基础。

基于微生物燃料电池技术的生物传感器及其应用进展

简要介绍微生物燃料电池型生物传感器的工作原理,概述各种基于微生物燃料电池技术开发的生物传感器及其应用领域。分析影响微生物燃料电池型生物传感器性能的因素,讨论提高传感器性能的方法,以期为研究和开发高性能的微生物燃料电池型生物传感器提供参考。

快速检测细菌总数的便携式生物荧光传感器

细菌数与细菌中三磷酸腺苷(ATP)含量成比例,可通过生物荧光法检测细菌中ATP含量,间接获得细菌总数。研制了一种便携式生物荧光传感器,可依次进行细菌ATP的提取和检测,最终实现对细菌总数的快速检测。以十六烷基三甲基溴化铵(CTMAB)作为细菌ATP提取剂,当CTMAB浓度为5mmol/L、提取时间2min、中和剂浓度为5mmol/L时,ATP提取效率最高。在优化的实验条件下,传感器响应光强与细菌总数线性相关,线性范围58～5.89×107cfu/mL,相关系数达0.979。传感器检测结果与传统方法吻合,线性相关系数为0.873,满足现场使用要求。从加样到ATP提取到最后获得检测结果所需总时间小于5min。所研制的传感器具有操作简单、易于携带、成本低,适用于食品卫生质量控制、环境检测等领域的细菌总数现场检测。

BOD快速测定传感器的微生物膜固定方法研究

分别采用海藻酸钠包埋法、醋酸纤维素夹层法、戊二醛－牛血清白蛋白交联法等几种物理、化学方法制备固定化微生物膜，并采用自制的微生物ＢＯＤ传感器试验了各种膜对电极响应灵敏度、线性范围、响应时间、稳定性和寿命等性能的影响。比较了不同ｐＨ、温度和交联剂、包埋剂用量下该传感器的性能，获得了较满意的结果。实验表明，以交联法制备的传感器性能最佳，电极寿命达４０ｄ，测定ＢＯＤ值时间为１０－１５ｍｉｎ，方法的重现性和精密度均达ＢＯＤ测定要求。本研究对于实现快速测定ＢＯＤ传感器的商品化具有重要意义。