Biomass monitoring by use of a continuous on-line optical sensor

An optical sensor for on-line biomass monitoring was developed and implemented with a flow-through cell and a continuous sampling line to monitor cell concentrations in solutions of water and diluted molasses. Calibration curves, errors curve, flow rate effects and measurements comparing obtained values using the optical sensor and dry cell weight method were analysed. The calibration curves using cell cultures in tap water and molasses present an exponential profile in the range 5–40 g cell l−1 corresponding to 0–250 mV output signal. The output signal for biomass free molasses solutions was used for reference and compensation effects. A simple correlation for molasses compensation was determined and good reproducibility was obtained between experimental and calculated values for a wide range of biomass–molasses–water solutions.