FIA for on-line monitoring of important lactic acid fermentation variables.

An automated system with semi on-line monitoring of glucose, lactic acid, protein, and optical density during lactic acid fermentations, is set up to study the dynamics of lactic acid bacteria. The analyzers for glucose, lactic acid, and protein are based on flow injection analysis (FIA). The system consists of a laboratory fermentor with a continuous withdrawal system and an analysis system where glucose, lactic acid, and protein concentration are measured together with the optical density of the fermentor sample. The system is controlled by a personal computer.The system response is fast, and it yields a large number of reliable and precise analytical data, whoch is of great importance for mathematical model building. Some premliminary results are shown.