Influence Of Chiral Au Cluster On Growth Of Electrochemically Active Microorganism And Electrochemical Behavior Of Cytochromes

Microbial fuel cell(MFC)is a new technology with wide application prospects in energy supply and sewage treatment.However,the output power and electron transfer efficiency of MFC are severely limited by the extracellular electron transfer process of electrochemically active microorganisms.In order to further explore the extracellular electron transfer behavior of electrochemically active microorganisms,and try to enhance electron transfer efficiency,based on the special properties of gold nanocluster s(Au NC)and the role of electron mediators in the extracellular electron transfer process,gold nanoclusters with specific structures were synthesized to explore the effects of gold clusters on extracellular electron transfer,growth and reproduction of e lectrochemically active microorganisms.Gold clusters usually have active electrochemical properties and good biocompatibility by selecting appropriate ligands.In this dissertation,R-BINAP and S-BINAP were used as ligands to synthesize two kinds of gold clusters,and their structures were determined as [Au3[(R)-BINAP]3]+ and [Au3[(S)-BINAP]3]+ by UV-visible spectroscopy,circular dichroism spectroscopy,nuclear magnetic resonance,and mass spectrometry,respectively.After the tolerance experiment,the optimal incubation concentration of the two chiral gold clusters was finally determined to be 10 mg/m L.The measurement of the growth curve showed that the S chiral molecule slightly promoted the growth of bacteria compared to the R chiral molecule.During the cultivation process,a significant change was found in the behavior of the flora,the growth state of the flora was changed from suspension and dispersion to aggregation,and a single large bacterial colony was formed in the liquid medium.The S-type gold cluster was closely bound to the flora,the average absorption rate of bacteria to R-type molecules is 1.96%,and the average absorption rate of S-type molecules is 2.56%.Then this paper was intended to introduce the interaction between the obtained gold cluster and the conserved functional group iron porphyrin in the respiratory chain protei n,a theoretical calculation was carried out.The calculation results show that the binding energy of the R-type molecule to the gold cluster is-0.18 e V,and the binding energy of the S-type molecule to the gold cluster is-0.72 e V,both gold clusters can be stably combined with porphyrin iron,and the binding of S-type molecules is more stable.DPV results showed that Au NC(S)has positive effect on electrochemical behavior of cytochrome C.The observation of the effect of gold clusters on the flora from sus pension to aggregation is instructive for the study of biofilm formation and the extracellular electron transport behavior that occurs in biofilms in microbial fuel cells...