Biotransformation of sucrose rich Maple syrups into fructooligosaccharides, oligolevans and levans using levansucrase biocatalyst: Bioprocess optimization and prebiotic activity assessment

Abstract

Maple syrup was investigated as a source to produce FOSs and β-(2-6)-linked-oligolevans/levans. The modulation of this biotransformation was achieved through the control of Maple syrup °Bx and reaction conditions. Reaction time was identified as the most influential factor for the oligolevans/FOSs production in Maple syrup 30°Bx reaction system as well as for the oligolevans/levans synthesis in the 66°Bx one. In the predictive model of oligolevans/levans production in Maple syrup 60°Bx, the interactive effect between levansucrase unit and reaction time was significant (p-value of 0.0008). The optimal conditions for oligolevans/FOSs production (109.20 g/L) in Maple syrup 30°Bx were 3.73 U/mL, pH 6.60 and 23.12 h; while 5 U/mL, pH 6.04 and 29.92 h were identified as the optimal conditions for oligolevans/levans production (147.09 g/L) in Maple syrup 66°Bx. As compared to inulin-type commercial FOSs, the fermentation of oligolevans/FOSs from Maple syrup led to a higher count of Lactobacillus acidophilus and Bifidobacterium lactis and resulted in a higher production of lactic acid. This study lays the foundation for the biotransformation of Maple syrups into functional prebiotic ingredients.

Keywords: Bioncoversion; Biotransformation; Fructooligosaccharides; Levan; Levansucrase; Maple syrup; Oligolevan; Prebiotic activity.