EXPLOITATION OF THE ELECTROOPTICAL CHARACTERISTICS OF MICROBIAL SUSPENSIONS FOR DETERMINING P-NITROPHENOL AND MICROBIAL DEGRADATIVE ACTIVITY

The effect of p-nitrophenol metabolism on the electrophysical properti es of a microbial cell suspension of Acinetobacter calcoaceticum was i nvestigated. The dependence of the suspension's optical density change s due to the orientation of the electric field on the frequency of an orienting electric field (orientational spectra) over the range 10-10 000 kHz was used. Upon optimization of cell culture conditions, follow ed by orientational spectrum measurements, it was found that the most dramatic changes in orientation spectrum associated with p-nitrophenol metabolism took place over The frequency range 10-1000 kHz. Additiona lly, a linear dependence of the magnitude of the electrooptical effect on p-nitrophenol concentrations of 0.1-0.8 mM was established. The mi nimum p-nitrophenol concentration detectable by this calibration was 0 .1 mM. (C) 1998 Published by Elsevier Science B.V. All rights reserved .