Modeling and optimising alcohol production by fermentation of dextrose-xylose mixed feed using a fluorosensor

Dextrose with differing amounts of xylose (mixed substrate medium) has been fermented at 28 degree Celsius with sacchromyces cerevisiae (Baker's Yeast) as seeding. The progress of the reaction was recorded by measuring the fluorescent signal due to intracellular reduced nicotinamide adenine di nucleotide (NADH) present in the cells with a Dr. Ingold (Switzerland) fluorosensor which has an excitation wavelength of 360 nm and measurement wavelength of 450 nm. The concentration of xylose in the xylose-dextrose feed was varied from 0.7% to 5.0% by weight. The optimum concentration of xylose at which the production of alcohol was a maximum was found to be 3.4 percent xylose. The fluorescent voltage data for different concentration of xylose fitted a first order model with an average absolute deviation of less than one percent. Development of this model is useful in design of model predictive controllers.