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New instrument for on‐line viscosity measurement of fermentation media
Author(s) -
Picque D.,
Corrieu G.
Publication year - 1988
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260310104
Subject(s) - fermentation , signal (programming language) , viscosity , rheology , aeration , biological system , bioreactor , newtonian fluid , materials science , chemistry , computer science , mechanics , physics , food science , composite material , organic chemistry , biology , programming language
In an attempt to resolve the difficult problem of on‐line determination of the viscosity of non‐Newtonian fermentation media, the authors have used a vibrating rod sensor mounted on a bioreactor. The sensor signal decreases nonlinearly with increased apparent viscosity. Electronic filtering of the signal damps the interfering effect of aeration and mechanical agitation. Sensor drift is very low (0.03% of measured value per hour). On the rheological level the sensor is primarily an empirical tool that must be specifically calibarated for each fermentation process. Once this is accomplished, it becomes possible to establish linear or second‐degree correlations between the electrical signal from the sensor and the essential parameters of the ferementation process in question (pH of a feremented milk during acidification, concentration of extra cellular polysaccharide). In addition, by applying the power law to describe the rheological behavior of fermentation media, we observe a second‐order polynomial correlation between the sensor signal and the behavior index ( n ).