MULTIVARIATE APPROACH FOR THE SIMULTANEOUS DETERMINATION OF TOTAL BIOMASS AND GLUCOSE FROM A YEAST FERMENTATION BY SEQUENTIAL INJECTION-ANALYSIS

A simultaneous determination of total biomass and glucose was performe d using a simple sequential injection system with the full range of vi sible absorbance spectrum al the analytical signal. The assays were pe rformed on-line with no pre-treatment of the sample. fn the past, meas urement on unfiltered bioprocess samples have been avoided due to anti cipated problems such as cell aggregation, clogging of the flow system , cell adhesion to tubing walls and cross contamination. The sample wa s diluted, mixed with the glucose reagent in a stirred cell and the re sulting signal was collected as a function of time. Calibration models were determined using linear partial least square's regression and te sted by a cross-validation. The average difference between the model's prediction of total biomass and the dry weight determination was 5 %. The glucose model lacked quantitative predictive ability but could id entify pulse spikes in the Fermentation broth. The sampling frequency was 7 samples/h.