Estimation of Microbial Mass Concentration Based on Fluorometric Measurement of Cell Protein

概要

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To develop a convenient method for the estimation of microbial cell mass, the fluorescence intensity of protein (F_<290>) was measured in cell extracts from Escherichia coli, Ruminococcus albus, and Aspergillus niger. Cell extracts obtained by sodium dodeyl sulfate (SDS)-boiling treatment after sonication had high F_<290> intensities under an excitation wavelength (EXW) of 290 nm and an emission wavelength (EMW) of 340 nm. On the basis of the fluorescence spectra, we confirmed that the fluorescence of the extract was caused by protein in the cell, especially by tryptophan residues in the proteins. Carbohydrate, lipids, nucleic acids, and vitamins from the cells did not interfere significantly with the F_<290> intensity. The intensity and cell mass concentration were related linearly below 0.15 g-cell/l, and the ration of the intensity to the cell concentration was evaluated as a constant for each microorganism. It was thus possible to monitor the microbial cultures using the F_<290> intensity as an indicator, even in cultre systems where optical and gravimetric measurements of cell mass were not effective.
社団法人日本生物工学会の論文
1986-10-25