High throughput fermentation monitoring via bubble detection

Abstract

<p>The goal of this study was to develop a high throughput ethanol monitoring system incorporating the concept of multi channel bubble-based optical system, and to test this system at different sugar and yeast levels. Initially, single orifice chamber was built and tested at six controlled airflow rates. Although good correlations were observed between detected bubble volume and flow, bubble volumes were roughly 4x lower than injected volumes. The single orifice chamber was expanded to the eight orifice chamber and the bubble count and diameter was estimated using the program written in Matlab. Controlled injection tests established that bubble volume output was in the range of 30% to 64% of the injected volume. However, when the system was tested with fermentation reactors providing gas to the orifices, the correlation between computer-detected carbon dioxide values and HPLC estimated ethanol values was extremely low (R² < 0.1). Programming difficulties prevented further analysis of the data, and it is unclear whether the problems of bubble size variation and grouping can be overcome with this method.</p>