Continuous generation of fructose from Taraxacum officinale tap root extract and inulin by immobilized inulinase in a packed-bed reactor

Production of exo-inulinase from newly isolated Aspergillus niger was statistically optimized using dandelion tap root extract (% fresh w/v) resulting in a ~2.5 fold (2337 nkat/ml) enhancement. Exo-inulinase (1166 nkat/mg) immobilized in Ca-alginate beads was used for continuous generation of fructose from crude inulin extracted from Taraxacum officinale (dandelion) and chicory juice. Immobilized enzyme was optimally active at 50 °C and pH 5.0 and the kinetic parameters evaluated were 3.74 mM (Km) and 1.62 µm/min (Vmax). Continuous generation of fructose syrup from low-cost dandelion root extract and chicory inulin using a packed bed bioreactor prepared with exo-inulinase immobilized in alginate beads was demonstrated. Successive degradation of dandelion oligosaccharides and fructans to pure fructose was observed over 30 days period. The bioreactor had a half-life of 15 days and more than 90% (w/w) yield of fructose was observed. The study demonstrated use of a fructan-rich common weed for continuous production of fructose.

Graphical abstractLabels: 1. Dandelion tap root extract or pure chicory inulin; 2. Peristaltic pump; 3. Water inlet; 4. Substrate percolating on immobilized inulinase; 5. Glass vessel with water jacket; 6. Ca-alginate immobilized inulinase (biocatalyst) of Aspergillus niger; 7. Water outlet; 8. Generated fructose syrup; 9. HPLC chromatogram showing fructose syrup generation.Download high-res image (83KB)Download full-size image