Fructans are fructose-based polymers, defined as fructooligosaccharides (FOS), when they possess a short chain. These molecules are highly appreciated in the food and pharmaceutical international market and have an increasing demand worldwide, mainly for their prebiotic activity and, therefore, for all their health benefits to those who consume them constantly. Thus, new natural or alternative FOS production systems of industrial scale are needed. In this regard, microorganisms (prokaryotes and eukaryotes) have the potential to produce them through a wide and diverse number of enzymes with fructosyltransferase activity, which add a fructosyl group to sucrose or FOS molecules to elongate their chain. Microbial fructosyltransferases are preferred in the industry because of their high FOS production yields. Some of these enzymes include levansucrases, inulosucrases, and β-fructofuranosidases obtained and used through biotechnological tools to enhance their fructosyltransferase activity. In addition, characterizing new microorganisms with fructosyltransferase activity and modifying them could help to increase the production of FOS with a specific degree of polymerization and reduce the FOS production time, thus easing FOS obtention. Therefore, the aim of this review is to compile, discuss, and propose new perspectives about the microbial potential for FOS production through enzymes with fructosyltransferase activity and describe the modulation of FOS production yields by exogenous stimuli and endogenous modifications.

Fructooligosaccharides (FOS) are short fructans with different degrees of polymerization (DP) and bonds in their structure, generated by the distinct activities of fructosyltransferase enzymes, which produce distinct types of links. FOS are in high demand on the market, mainly because of their prebiotic effects. In recent years, depending on the link type in the FOS structure, prebiotic activity has been shown to be increased. Studies on β-fructanofuranosidases (Ffasa), enzymes with fructosyltransferase activity in yeasts, have reported the production of ¹F-FOS, ⁶F-FOS, and ⁶G-FOS. The aims of this investigation were to evaluate the capability of fifteen different yeasts to grow in Agave sp. juices and to determine the potential of these juices as substrates for FOS production. Additionally, the research aimed to corroborate and analyze the fructosyltransferase activity of enzymatic extracts obtained from agave yeasts by distinct induction media and to identify the role and optimal parameters (time and sucrose and glucose concentrations) for FOS and disaccharides production through Box–Behnken designs. To carry out such a task, different techniques were employed: FT-IR, TLC, and HPAEC-PAD. We found two yeasts with fructosyltransferase activity, P. kudriavzevii ITMLB97 and C. lusitaniae ITMLB85. In addition, within the most relevant results, the production of the FOS 1-kestose, 6-kestose, and neokestose, as well as disaccharides inulobiose, levanobiose, and blastose, molecules with potential applications, was determined. Overall, FOS production requires suitable yeast species, which grow in a medium under optimal conditions, from which microbial enzymes with industrial potential can be obtained.

FOS are short fructans with different DP and bonds in their structure, generated by the distinct activities of fructosyltransferase enzymes, which produce distinct types of links. FOS are highly demanded on the market, principally for their prebiotic effects. In recent years it has been described that depending on the link type in FOS structure, their prebiotic activity could be enhanced. Studies about β-fructanofuranosidases (FFasa), enzymes with fructosyltransferase activity in yeast, have reported the produc-tion of 1F-FOS, 6F-FOS, and 6G-FOS. The aims of this work were to evaluate the fructo-syltransferase activity of fifteen yeasts, determine the potential of agave juice as a sub-strate for FOS production, evaluate the fructosyltransferase activity of yeast enzymatic extracts generated by distinct induction media, and determine optimal parameters for FOS production using yeast isolated from agave. To carry out such a task, different techniques were employed: FT-IR, TLC, and HPAEC-PAD. We found two yeasts with fructosyltransferase activity, P. kudriavzevii ITMLB97 and C. lusitaniae ITMLB85. In addition, within the most relevant results, the production of the FOS: kestose, 6-kestose, and neokestose, as well as disaccharides: inulobiose, levanobiose, and blas-tose were determined, which are molecules with future potential applications. Overall, FOS production requires suitable yeasts, which grow in a medium under optimal con-ditions, from which microbial enzymes with industrial potential can be obtained.