BIOMASS MEASUREMENT BY INDUCTIVE PERMITTIVITY

An electrodeless, inductive permittivity probe is shown to reliably in dicate fermentation biomass. By designing the probe based on electroma gnetic induction, the electrode polarization artifact - common to elec trode-based permittivity measurements of conductive solutions - is eli minated. The measurement of viable biomass concentration (X-V) is prec ise and linear, with negligible interference, as shown for two bacteri a, two yeasts, and two mammalian cells. The permittivity spectra often can be described by the three parameters of the Cole-Cole equation: t he maximum (low-frequency) permittivity, the characteristic frequency (f(c)), and the Cole-Cole alpha. The f(c) and alpha have potential as relative indicators of cell size and morphology, respectively. (C) 199 7 John Wiley & Sons, Inc.