Measurement of Specific Growth Rate with Fractal Dimension in Bioprocess

Abstract

A procedure for measurement of microbial activity becomes important in controling bioprocesses. This paper describes an on-line measurement method of a specific growth rate which is an index for the microbial activity. The specific growth rate is measured with a fractal dimension applied to a spacial pattern for a growing microorganism.
The relation between the fractal dimension and the specific growth rate is obtained through entropy of the pattern for the growing microorganism in the bioprocess. To clarify the procedure for measurement, a stochastic model of the measurement method is proposed for the growing pattern specified by the fractal dimension.
The fractal dimensions are calculated with image data for 4 kind of yeast. Based on the method, the results are compared with the experimental ones.