Measurements of Oxidoreductase-like Activity of Intact Bacterial Cells by an Amperometric Method Using a Membrane-Coated Electrode

Abstract

The oxidation of D-glucose and nicotinic acid by intact cells of Gluconobacter industrious and Pseudomonas fluorescens, respectively, is successfully measured by an amperometric method using such compounds as Fe(CN)6(3-), p-benzoquinone, and dichlorophenolindophenol as electron acceptors. Analysis of the experimental results reveals that the intact cells behave like oxidoreductases whose kinetics follows a Michaelis-Mententype equation. The catalytic behavior is explained by a model which treats the bacterial cells as bags of enzymes and assumes distribution equilibrium in the concentrations of both the substrate and the electron acceptor between the test solution and the medium within the cells. The catalytic activity can be characterized by three quantities: the maximum reaction rate (vB) and the ratios of the Michaelis constant to the distribution constant for the substrate (Ks,cell/Ks,p) and to that for the electron acceptor (KM,cell/KM,p). Advanced modification of the model to involve the membrane permeability reveals that the three quantities are effective for explaining the catalytic behavior even when the permeability effect is significant. Thus, the three quantities should be regarded as the parameters which can reflect the permeability effect.

Testing of Bacteria Gluconobacter oxydans and Electron Transport Mediators Composition for Application in Biofuel Cell

“…The work [14] describes an amperometric biosensor for ethanol detection, which is modified by HCF and contains the bacterium G. oxydans CCM 1783 (ATCC 621). DCPIP and BQ were used in combination with the suspension of G. industrius (IFO 3260) for current generation at electrocatalytic glucose oxidation [15]. We have found no literature data on assessment of the efficiency of mediators at their application in combination with the same strain.…”

Bioelectrocatalytic Oxidation of Glucose by Immobilized Bacteria Gluconobacter oxydans. Evaluation of Water‐Insoluble Mediator Efficiency

“…The rate of electrocatalytic glucose oxidation by bacterial cells was assessed by analyzing the dependences I -t [16]. The current is proportional to reaction rate:…”

“…The work of T. Ikeda et al [16] is apparently fundamental in this respect. The authors have shown that the catalytic activity of the system "mediator -bacterial cell" can be characterized by three quantities: the maximum reaction rate and the ratios of the Michaelis constant to the distribution constant for the substrate (K S /K S,p ) and to that for the electron acceptor (K M /K M,p ).…”

“…In contrast to water-soluble mediators described in [16], we have considered mediators insoluble in the water phase. Bacterial cells of Gluconobacter oxydans sbsp.…”

Electrochemical regulation of the end‐product profile in Propionibacterium freudenreichii ET‐3 with an endogenous mediator

“…To achieve the continuous electron transfer (i.e., electron leak) from microbial cells with minimum amounts of external artificial electron acceptors (or to reduce the amounts and cost of external artificial electron acceptors), the re-oxidation reaction of the reduced form of the artificial electron acceptors would be required. When an electrode was used as a final electron acceptor, the artificial electron acceptor works as a mediator to shuttle electrons from the microbe to the electrode (Ikeda et al, 1996;Kim and Kim, 1988). The electrochemical metabolic regulation of P. freudenreichii has also been studied using hexacyanoferrate (III) as an artificial mediator (Emde and Schink, 1990).…”