Sire-technology. Part III. Glucose monitoring during fermentation of a lignocellulosic hydrolysate by Saccharomyces cerevisiae employing a differential amperometric biosensor

A biosensor with an Injectable recognition element (SIRE-biosensor) was used to measure the glucose concentration in undiluted samples from a fermentation of a hardwood hydrolysate. Glucose oxidase (1 mg/ml, 184.9 U/ml) was used as the recognition element in combination with an amperometric transducer. The results obtained with the SIRE-biosensor showed a good correlation to those obtained with an established analytical procedure (HPLC). The correlation coefficient and regression line between the two methods were r = 0.996 and y = 0.86x - 0.21. Thus, the results from the SIRE-biosensor were slightly lower than those obtained with HPLC, and the reasons herein are discussed. The SIRE-biosensor had a sampling frequency of 12 samples per hour, whereas the HPLC only allowed measurements of 1.2 samples per hour and required dilution of the samples. Additionally, the SIRE-biosensor measurements do not require any sample preparation, thus suggesting that the sensor can be used for in situ monitoring of fermentation processes.