Applications Of Immbolized Miceooeganism In Electrochemical Toxic Testing Field

ObjectiveIn recent years, with the rapid development of industry and agriculture, problems of chemical abuse are increasingly prominent. Especially for the widespread use of some toxic and hazardous substances, which is becoming a serious impact on water ecological system through direct discharge and penetration, have already directly threatened human health and daily life, Control and prevention the chemicals pollution is one of the important means to solve water pollutions and deficiencies in China. Therefore, acting as a role of "eyes" in the water quality control, how to improve the existing method and develop more effective new method of long-term water monitoring and rapid water quality detection has become a hotspot of academic research. The immobilized microorganism technique is widely used in the biological degradation and water quality testing because of its advantages on good biological stability, high activity, simple process and low price. This paper attempted to use different colloidal to embed Escherichia coli ?E. coli?. To combine with the electrochemical technique, we constructed a fast, sensitive electrochemical bio-system based on immobilized E. coli to enhance utility of biological technique in the field of water quality monitoring and detection.MethodsA quality control strain of E. coli ATCC 25922 was as the embedded microorganism, and K₃[Fe?CN?₆] was used as probe for electrochemical biological detection. The information of microbial activities changes was obtained by monitoring the reduction product ([Fe?CN?₆]^4-) of [Fe?CN?₆]^3-. The concentrations of embedding materials and embedded E. coli was screened based on the theory mentioned above, Then the storage period and mechanical strength of composite colloidal particles made by different embedding materials were determined. The different kinds of composite colloidal particles with embedded microorganisms were used to detect the toxicity of 3,5-dichlorophenol ?DCP? in order to screen the most suitable embedding method for toxicity detection. Under optical conditions, the composite colloidal particles with embedded E. coli were used to detect the toxicities of real water samples and toxin contained water samples.ResultsIn this paper, the tested polymers of the polyvinyl alcohol ?PVA? embedding was the best, followed by chitosan, agar-gelatin, agar, gelatin embedding was worst. By doping calcium carbonate ?CaCO₃?, activated carbon ?AC?, silicon dioxide ?SiO₂? and sodium alginate ?SA? preferably the biological activity of four kinds of additives to improve the PVA poor permeability defects and improve the material hardness and biocompatibility immobilized microorganism particles. Based on screened optimum conditions, embedded bacteria in all kinds of composites were employed to detected the toxicity of 3,5-dichlorophenol ?DCP?. The experimental results showed that the sensitivity of embedded bacteria in different composites to the poison DCP in descending was SA> AC> CaCO₃> SiO₂.Construction of electrochemical detection method ferricyanide as a probe, and explore the polyvinyl alcohol ?PVA? and additive sodium alginate ?SA?, activated carbon ?AC? total solid embedded E. coli microorganism toxic particles in a water sample analysis laboratory waste, mixed poison 3,5 dichlorophenol ?DCP?, pesticides and herbicides ethirimol five cyanide alachlor in application performance. This indicates that the addition of additives after PVA immobilized microorganisms sensor poisons and significantly improve the sensitivity, can be effectively used in aquatic toxicity testing.ConclusionsIn this paper, a variety of embedded vector screened for E. coli fixed to determine the optimal pretreatment conditions optimal embedding carrier. Will be applied to toxic water samples and water samples toxicity testing, the results showed that the PVA, SA and activated carbon ?AC? at the same time prepared by blending the three PVA-SA-AC blending particles embedded E. coli strain optimization cell activity and the highest sensitivity to poison toxic, has good prospects in pharmaceutical synthesis intermediates and monitor water toxicity detection.