Effect of some factors on determination of viable microbial cells by peroxyoxalate chemiluminescence method |
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Authors: | Sang Kon Oh Seung Hee Cha |
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Institution: | Agency for Defence Development, Advanced Technology Research Center, Yuseong, Taejon, South Korea |
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Abstract: | The effects of physical and chemical factors on the production of H2O2 from Escherichia coli cells were studied. When 20 mmol 1-1 Tris-HCl buffer was used for this purpose the electron transport system (ETS) showed the highest activity at pH 7.6-8.2. KCN promoted the production of H2O2 from E. coli cells, and the optimum concentration was changed in different reaction times and pH values. Glucose, 5 mg ml-1, increased the ETS activity about twofold. The other substrates and surfactants did not increase the chemiluminescence intensity. NaNO2 and Na2SO4 in inorganic salts significantly reduced the ETS activity above 70%. In addition, the optimum temperature for the production of H2O2 was 30°C in this study. When glucose (5 mg ml-1) and KCN (0.2 mmol 1-1) were added to the reaction buffer containing 0.5 mmol 1-1 menadione, the detectable minimum cell densities (averages of triplicate assay) of E. coli, Enterobacter cloacae and Serratia marcescens were 5 times 103 cells ml-1, 104 cells ml-1 and 104 cells ml-1 respectively. |
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