Optimization of kestose production by a Saccharomyces cerevisiae invertase exhibiting selective transfructosylation

BACKGROUND Kestoses, short‐chain fructooligosaccharides (FOSs), are valued for their intestinal, immunomodulatory, sweetness, and prebiotic properties compared with longer‐chain FOSs. Although invertases are widely used for kestose production, most enzymes generate mixed FOS products. This study investigates a GH32 invertase from Saccharomyces cerevisiae (ScINV), heterologously expressed in Escherichia coli , with an emphasis on its product selectivity for kestose production. RESULTS Under optimized conditions (600 g L −1 initial sucrose concentration, 1.0 μmol L −1 enzyme, pH 6.0, and 45 °C), ScINV produced 54.1 g L −1 kestoses after 24 h, corresponding to a yield of 9.0% and a purity of 7.5%. Purification by ligand‐exchange chromatography using XA2004‐30‐Ca resin increased kestose purity to 19.4% with complete recovery, whereas higher‐resolution fractionation achieved 100% purity with a reduced recovery of 14.9%. CONCLUSION ScINV exhibits selective kestose production without formation of higher‐degree FOSs. Although partial peak overlap limits single‐step recovery, purification using XA2004‐30‐Ca resin provides a promising basis for scale‐up. Coupling this approach with continuous simulated moving bed technology may improve process efficiency and industrial feasibility.