A New On-Line Indicator of Biopolymer Content in Bacterial Cultures

This paper describes the application of an impedance spectroscopy based analyser in combination with standard off-gas measurements for on-line monitoring of an intracellular biopolymer accumulation during a bioproduction process (Pseudomonas putida KT2442 fed-batch cultivation). Using exclusively on-line measurements a new physiological indicator of biopolymer accumulation in bacterial cells is proposed. The indicator, which could be referred to as an “obesity” quotient, is based on capacitance difference signal carrying information on number of cells and cumulative oxygen consumption related to dry cell weight.