Fluorimetric technique for monitoring changes in the level of reduced nicotinamide nucleotides in continuous cultures of microorganisms.

A metabolite fluorimeter was modified to monitor nicotinamide nucleotides in cells growing in a chemostat culture. By illuminating and collecting fluorescence over a relatively large area of the side of the culture vessel, the noise level was kept low even in highly turbulent cultures. Calibration of the system was by enzymatic assay of samples. Changes in nicotinamide nucleotide of concentration less than 0.1 nmoles/ml could be detected [i.e., less than 10% aerobic/anaerobic response for a cell concentration of 5 mg (dry wt) per ml].