Application of a luminescence-based pH optrode to monitoring of fermentation by Klebsiella pneumoniae

The application of an optical sensor based on immobilization of the ruthenium complex [Ru(bpy) 2(dhphen)] 2+ (bpy=2,2′-bipyridine, dhphen=4,7-dihydroxy-1,10-phenanthroline) in Nafion to pH monitoring of fermentation by Klebsiella pneumoniae is described. Interference from the culture medium can be eliminated by addition of a black microporous filter membrane (pore size: 0.45 μm) on top of the sensing film. The response of this pH optrode was found to show good correlation with the conventional pH electrode.