Development of Biocatalytic Functional Column Electrolytic Method for Application to High-Performance Biotransformation and Absolute and Sensitive Analysis.

Focusing our attention to a biotransformation system from nicotinic acid(NA)into6-hydroxynicotinic acid(6HNA)by Pseudomonas fluorescens TN-5，the electron transfer from the cell to column electrodes has been realized using ferricyanide as an exogenous electron acceptor。The hydoxylation is remarkably accelerated using such exogenous electron transfer mediator，in place of the native final electron acceptor O I D 22 ii D 2.In addition，the succeeding reaction of6HNA can be completely suppressed by the use of the exogenous electron transfer mediator.Based on the results，an electrochemically accelerated and 100%biotransformation system has been realized on our column electrolytic system，where Pseudomonas fluorescens TN-5cells were immobilized on a column electrode。Such complete biotransformation of NA into6HNA is the first case.This method would be applied to the production of 6HNA as an important starting material of pesticides.In addition，this method can be successfully applied to the evaluation of the number of NA dehydrogenase in a single cell，where the enzyme immobilized on the column is reduced with NA and after then the reduced enzyme is electrochemically re-oxidized.Based on a similized on the column is reduced with NA and after then the reduced enzyme is electrochemically re-oxidized.Based on a similized.Based on a similar principle，NA biis electrochemically oxed pized portant starting material of pesticides.The coulometric analysis has allowed highly sensitive and absolute determination of NA down to 0.2pmol。

Focusing our attention to a biotransformation system from nicotinic acid (NA) into 6-hydroxynicotinic acid (6HNA) by Pseudomonas fluorescens TN-5, the electron transfer from the cell to column electrodes has been realized using ferricyanide as an exogenous electron acceptor. The hydoxylation is remarkably accelerated using such exogenous electron transfer mediator, in place of the native final electron acceptor OィイD22ィエD2. In addition, the succeeding reaction of 6HNA can be completely suppressed by the use of the exogenous electron transfer mediator.Based on the results, an electrochemically accelerated and 100% biotransformation system has been realized on our column electrolytic system, where Pseudomonas fluorescens TN-5 cells were immobilized on a column electrode. Such complete biotransformation of NA into 6HNA is the first case. This method would be applied to the production of 6HNA as an important starting material of pesticides.In addition, this method can be successfully applied to the evaluation of the number of NA dehydrogenase in a single cell, where the enzyme immobilized on the column is reduced with NA and after then the reduced enzyme is electrochemically re-oxidized.Based on a similar principle, NA is bioelectrochemically oxidized at Pseudomonas fluorescens TN-5 cell-immobilized column electrode. The coulometric analysis has allowed highly sensitive and absolute determination of NA down to 0.2 pmol.