Innovative Immobilization of <i>Aspergillus aculeatus</i> OI4C2 Fructosyltransferase on MANAE-Agarose Cross-Linked with Genipin for Enhanced Production of Fructooligosaccharides

This study evaluated the use of genipin in monoamino-<i>N</i>-aminoethyl (MANAE)-agarose in the immobilization of fructosyltransferase (FTase) from <i>Aspergillus aculeatus</i> OI4C2, focusing on the stability and catalytic efficiency for the production of fructooligosaccharides (FOS) from sucrose. The immobilization of FTase on genipin-cross-linked MANAE-agarose achieved a 98.53% yield, 76.71% activity recovery, and 77.86% efficiency, and it resulted in the synthesis of predominantly short-chain fructooligosaccharides. Comparatively, the maximum amounts of FOS obtained were 73.44 g L^-1 for the free enzyme and 97.37 g L^-1 for the immobilized enzyme. Immobilization improved the thermal stability at 40-60 °C and increased the enzyme stability under acidic pH conditions (4.5-6.5) for up to 72 h. The operational stability of the immobilized enzyme retained 50% of its initial activity after 12 reuse cycles. These results indicate that <i>A. aculeatus</i> FTase immobilized on MANAE-agarose-genipin is a promising biocatalyst for large-scale FOS production, with prospects in the food, pharmaceutical, and nutraceutical industries.