Research And Improvement Of On-line Glucose Analyzer Used In Fermentation

The glucose concentration in the fermentation broth directly affect the yield andquality of the fermentation product in the fermentation industry, so the real timemonitoring of the glucose concentration is extremely important. Fermentationequipment, however, needs to withstand high temperature and pressure, and to avoidcontamination broth. As a result, traditional biosensors difficult to achieve on-linemonitoring. Currently, the main mode used to the monitor the broth glucoseconcentration is offline, and online mode is still in the experimental stage.In this thesis, an original enzyme-injected glucose analyzer for on-linemonitoring of fermentation broth is researched and improved. Using the dialysismethod, The analyzer obtains the liquid samples for test from the fermentation tank.Its chemical reaction mechanism is the principle of the first generation enzymeelectrode, which using oxygen as an electron transfer agent, glucose in test solution iscatalyzed by the solution of glucose oxidase, and its product electrochemical react atthe electrode. The concentration of glucose solution can be determined by detectingthe current size, and the results are displayed in the host machine.This thesis analyzes both deficiencies in the existing enzyme-injected on-lineglucose analyzers and made new approaches to improve it.The first drawback is the instability of the dialysis sampling system of theoriginal analyzer. The reasons of the instability is dialyzed, and interference on theresult of the monitoring is introduced. Faced to the lack of dialysis sampling method,fabrication sampling is proposed. The filtration sampling probe was designed,fabricated and tested, which uses cross-flow filtration technology and can beconnected to the fermentation tank directly. The analyzer continuous access to sterilebroth by the probe. The probe can effectively prevent the intrusion of external bacteriafrom broth in fermentation tank. On-line sampling is achieved by filtration samplingprobe, which achieves on-line measurement combining with the enzyme-injectedglucose biosensor.The second drawback is the use of software in a desktop PC as human-computerinteraction module, to control, operate, show the results and so on, so that the entiredevice structure is complex and cumbersome. To address this deficiency, solutionwith an embedded touch PC instead of the original PC in order to reduce the volume and complexity of the device is presented. The human-machine interface, anapplication that runs on the Windows CE operating system, which use LJD-eWin5SEmbedded Touch PC manufactured by Blue Ocean Microchip as the implementationplatform, is developed using MFC (Microsoft Foundation Classes). The software wasdeveloped, debugged and the various functional modules was achieved after theanalysis of the requirements, the design of the system architecture and the runprocesses.By these two improvements, the error caused by fermentation broth sampling inthe original analyzer is decrease effectively, the stability of the analyzer is improved,and the complexity of the structure is reduced.