On-line monitoring of fermentation processes by a new remote dispersive middle-infrared spectrometer

A middle infrared spectrometer coupled with a new attenuated total reflecta nce probe by optical fibres was developed to solve the problem of on-line a nalysis in the bioreactors. The measurement of sugars, ethanol and organic acid concentrations was investigated during alcoholic and lactic fermentati ons. This apparatus was able to operate between 5.5 and 10.5 mu m with a re asonably good repeatability (CV < 5%) between 6 and 10 mu m. The standard e rrors of prediction were between 1.4 g l(-1) (for galactose) and 3.5 g l(-1 ) (for fructose). (C) 2000 Elsevier Science Ltd. All rights reserved.