Measurement of intracellular adenosine-triphosphate using an on-line FIA system for determination of microorganism cells number

Abstract

An on-line FIA system was developed for intracellular ATP measurement in a culture fluid and measurement conditions were examined. This system was then used for intracellular ATP measurement in microorganisms. ATP concentration was measured by bioluminescent reaction using luciferase and luciferin. Only about 5 min were required to measure intracellular ATP and free ATP concentrations. Luminescence response was linear from 1 nmol/l to 10 μmol/l. Measurement time could be over 7 d long to preserve the enzyme solution and ATP standard at 4 °C in the cooling container. Intracellular ATP was measured in culture fluids of yeast and E. coli. There was good correlation between intracellular ATP concentration and viable cells number. For yeast cells, the correlation coefficient and R.S.D. were 0.992, lower than 3%. The results of the present system agreed with conventional one well.