Recent developments in the production of prebiotic fructooligosaccharides using fungal fructosyltransferases

Prebiotic nutritional ingredients have received attention due to their health-promoting potential and related uses in the food and nutraceutical industries. Recent times have witnessed an increasing interest in the use of fructooligosaccharides (FOS) as prebiotics and their generation using microbial enzymes. FOS consumption is known to confer health benefits such as protection against colon cancer, improved mineral absorption, lowering effect on serum lipid and cholesterol concentration, antioxidant properties, favourable dietary modulation of the human colonic microbiota, and immuno-modulatory effects. Comparative analysis of molecular models of various fructosyltransferases (FTases) reveals the mechanism of action and interaction of substrate with the active site. Microbial FTases carry out transfructosylation of sucrose into fructooligosaccharides (kestose, nystose, and fructofuranosylnystose), the most predominantly used prebiotic oligosaccharides. Furthermore, FOS has also been used for other purposes, such as low-calorie sweeteners, dietary fibres, and as the substrates for fermentation. This review highlights the occurrence, characteristics, immobilisation, and potential applications of FOS-generating fungal FTases. Production, heterologous expression, molecular characteristics, and modelling of fungal FTases underpinning their biotechnological prospects are also discussed.