微生物应用技术6

1、第八章 微生物燃料电池与生物传感器n燃料电池定义n燃料电池构造及与原电池的区别燃料电池的特点n1、高效率n2、高可靠性n3、良好的环境效益n4、良好的操作性能n5、高度灵活性n6、发展潜力巨大燃料电池存在问题n价格昂贵n高温时寿命及稳定性有待提高n技术不够普及n燃料供应体系单一燃料电池研究历史n1839年发现使用铂电极电解硫酸时，在两极产生电势差n50年代，培根开发碱式电池系统，60年代用于阿波罗计划n90年代，质子交换膜燃料电池生物燃料电池n利用生物催化剂将化学能转变为电能n特点：1、原料广泛2、操作条件温和3、生物相容性好酶燃料电池n主要使用脱氢酶与氧化酶n原料为甲醇和葡萄糖n特点：1、发

2、电2、生产生化产品微生物燃料电池n菌种（细菌或微藻）n介体n特点：1、处理污水2、利用污水中的有机废物发电微生物燃料电池微生物燃料电池（Microbial fuel cell） A Microbial Fuel Cell is a device that converts chemical energy to electrical energy by the catalytic reaction of microorganisms. A typical microbial fuel cell consists of anode and cathode compartments separate

3、d by a cation specific membrane. In the anode compartment, fuel is oxidized by microbe generating electrons and protons. Electrons are transferred to the cathode compartment through the circuit, and the protons through the membrane. Electrons and protons are consumed in the cathode compartment reduc

4、ing oxygen to water. In general, there are two types of microbial fuel cell, mediator- and mediator-less microbial fuel cell.A typical Microbial Fuel cellMicrobial fuel cell cleans water, generates electricitythe Penn State experiments have produced between 10 and 50 milliWatts of power per square m

5、eter of electrode surface, or about 5 percent of the amount needed to run one mini-Christmas tree light, while removing up to 78 percent of organic matter as measured by biochemical oxygen demand (BOD). nDissimilatory metal-reducing microorganisms, such as Geobacter and Rhodoferax species, have the

6、novel ability to directly transfer electrons to the surface of electrodes. This had led to the construction of microbial fuel cells that are superior to previously described microbial fuel cells in that: nCurrent research is focusing on elucidating the mechanisms of electron transfer between the mic

7、roorganisms and the electrode in order to design better electrodes or genetically engineer better microbes for higher rates of electricity production. n1) that are much more efficient; n2) they do not require the addition of the toxic electron shuttling mediator compounds employed in previously desc

8、ribed microbial fuel cells; n3) they have remarkable long-term stability; and 4) it is possible to harvest electricity from many types of waste organic matter or renewable biomass. Immediate application of these microbial fuel cells will be for powering electronic monitoring devices in remote locati

9、ons, such as the bottom of the ocean. However, many other applications are possible. Gold electrode used in analysis of electron transfer rates of Geobacter species Geobacter colonizing a graphite electrode surface Geobacters in Boston Harbor sediments colonize electrodes placed in the mud to power

10、a timer “Geobatteries” powering a calculator Geobacter metallireducens colonized on unpolished graphite electrode Rhodoferax ferrireducens on Electrode Transmission Electron Micrograph of Rhodoferax ferrireducens. Model SUV powered by marine geobatteries 生物传感器n由固定化的生物材料与一适当的换能器件密切接触而构成的检测器件，换能器件能将生化

11、信号转换成可定量的电信号。n生物材料有固定化酶、微生物、抗原、抗体、生物体组织和微小器官、结合蛋白、植物血凝素、激素受体等生物传感器原理n生物材料与待测物质发生催化反应，生成一种使生物膜层下面的敏感层产生响应的物质n利用生物膜所引起的电子转移，从而改变电极电位的原理酶电极n包括电化学探头与附在探头表面上的固定化酶层，被测定物由被测系统扩散到固定化酶层，并把基质转化为产物，由酶层扩散到电化学探头，转化为电信号。微生物电极n利用微生物细胞代替酶，可保持较长时间的稳定性。n大多利用微生物整体的某些生理机能进行测定，分为呼吸活性测定型与代谢产物测定型免疫酶电极n利用抗体对抗原的识别和结合的功能研制而成

12、的生物电极，具有重复性强、敏感性高、专一性高和快速的特点。采用新型换能器件的生物电极n酶热敏生物电极适用于透光性差的粗制溶液或菌悬液第九章 微生物转化技术n在技术上比生产代谢物简单，多采用真菌，可用生长中的菌体、休止细胞、酶、固定化酶等。n转化特点：1、反应专一性2、区域专一性3、立体专一性特点：n菌体生长与转化分别进行n采用流加底物生物转化类型n甾体的生物转化n-紫萝酮羟基化n烷烃双端氧化n氧化脱氨n环氧化反应nC-C键脱氢反应n碳链氧化降解n碳双键加水反应n碳双键加氨反应n晴水化酶n脱氨甲酰基酶n转化茚甾体激素的微生物转化n专一性n产量高n反应条件温和n可在某一化合物特定的分子部位进行反应n利用几种微生物联合在不同部位进行反应甾体激素的微生物转化类型n1、羟基化n2、A环上C1 及C2 脱氢n3、甾醇侧链的降解微生物转化工艺n