Noninvasive Spectroscopy for Monitoring Cell Density in a Fermentation Process

Short-wavelength near-infrared spectroscopy in the wavelength range 700-1100 nm is used to monitor cell density in a fermentation process vessel over a wide concentration range (1-60 g/L). The measurement is performed noninvasively through the glass walls of the vessel using a bifurcated fiberoptic bundle to both excite the sample and collect the diffusely backscattered radiation. It was found that, in regions where there was tittle absorption, the major change was an exponential decrease of the logarithm of the diffusely backscattered radiation with increasing cell concentration. Various types of models were first to the data

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