Cross-linked whole cells for the sucrose transfructosylation reaction in a continuous reactor

Abstract

Fructooligosaccharides (FOS) are fructose oligomers beneficial to human health and nutrition for prebiotic sugars. Their production occurs by a transfructosylation reaction in sucrose molecules catalyzed by fructosyltransferase enzymes (FTase, E.C.2.4.1.9) adhered to microbial cells. The purpose of this work was to study the preparation, enzymatic activity, and stability of glutaraldehyde-crosslinked Aspergillus oryzae IPT-301 cells used as a biocatalyst for the transfructosylation reaction of sucrose in a packed bed reactor (PBR), aiming at FOS production. The highest transfructosylation activity (AT) was presented by the biocatalyst prepared by cross-linking at 200 rpm and 45 min. The highest AT in the PBR was obtained at 50 °C, with flow rates from 3 mL min-1 to 5 mL min-1 and sucrose concentrations of 473 g L-1 and 500 g L-1. The enzymatic kinetics was described using the Michaelis-Menten model. Finally, the biocatalyst showed constant AT of approximately 75 U g-1 and 300 U g-1 for 12 h of reaction in the PBR operating in continuous and discontinuous flow, respectively. These results demonstrate a high potential of glutaraldehyde-crosslinked A. oryzae IPT-301 cells as heterogeneous biocatalysts for the continuous production of FOS in PBR reactors.

Keywords

• fructosyltransferase
• whole cells
• heterogeneous biocatalysts
• packed bed reactors
• fructooligosaccharides