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

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.

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%.

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. © 2026 Society of Chemical Industry.