Optimization of xylitol and ethanol through the structured metabolic model of Debaryomyces hansenii Alvioni Bani(a), Kasbawati(a), Syamsuddin Toaha(a)
(a) Mathematics, Hasanuddin University, Makassar, Indonesia
Abstract
The cellular metabolic system is an intriguing subject for research, both theoretically and experimentally, in the field of bioprocessing. The research field of understanding cellular metabolism falls within the realm of mathematics, specifically involving mathematical models. A mathematical model is utilized to address typical challenges in bioprocessing. This study investigates the intracellular metabolism of Debaryomyces hansenii, which produces xylitol and ethanol using xylose and glucose as substrates. The substrates are obtained from the pretreatment of the lignocellulosic content in oil palm empty fruit bunches. This study considers fourteen variables representing its intracellular metabolism. Further sensitivity analysis was conducted on the parameters of the system using metabolic control analysis. This involved using parameter values obtained from published research. The sensitivity analysis yielded elasticity coefficients, metabolite control coefficients on xylitol concentration, and metabolite control coefficients on ethanol concentration. The results indicated that the inlet of hemicellulose (α-) had the highest positive coefficient for metabolite control on xylitol concentration and ethanol concentration, and the catalysis reaction by the xylitol dehydrogenase enzyme had the highest negative coefficient for xylitol whereas the catalysis reaction by pyruvate dehydrogenase enzyme for ethanol concentration. From the numerical simulation, several regulations were applied for increasing both products i.e. xylitol and ethanol, the best ways to increase the concentrations are by increasing the inlet of hemicellulose and increasing e_5^s reaction or catalysis by xylose reductase.
Keywords: Oil Palm Empty Fruit Bunches, Debaryomyces hansenii, Enzyme, Metabolic Control Analysis
