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Evaluation of Heat Resistance of Microorganisms by an Amperometric Measurement of the Microbial Substrate-Oxidizing Activity Using a Whole-CellModified Electrode

✍ Scribed by Tetsuya Kondo; Toshiyuki Ando; Tokuji Ikeda


Publisher
John Wiley and Sons
Year
2001
Tongue
English
Weight
106 KB
Volume
13
Category
Article
ISSN
1040-0397

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✦ Synopsis


A mediated bioelectrocatalysis using a bacterial cell-modi®ed electrode was applied to the evaluation of heat resistance of Escherichia coli and Lactobacillus plantarum. The ®rst derivative of the time course of the bioelectrocatalysis current for the bacterial D-glucose oxidation had a maximum d Iadt max at about 10 to 60 s after the addition of D-glucose to the solution. The d Iadt max value decreased in different manners depending on the conditions of heat treatment of the bacterial cells prior to their immobilization on electrode. The decreasing tendency in the d Iadt max value was similar to that in the colony formation unit measured by a conventional colony counting method. The d Iadt max method, which takes only 2 h, is much more time saving compared with the conventional method taking 24 h incubation for E. coli and 72 h incubation for L. plantarum. In some cases, however, there was a difference in the magnitude of relative decrease between the two methods, which could be attributed to the appearance of injured cells that were active in the d Iadt max measurement but not in the colony formation.