Simultaneous enzymatic synthesis and purification of prebiotic fructooligosaccharides in nanofiltration membrane module

Scientific breakthroughs in research of human microbiota revealed that significant number of diseases related to modern food intake and sedentary lifestyles are caused by dysbiosis of human microbiota composition, hence substantial increase in interest for products helping restore this balance (such as probiotics and prebiotics) within food, cosmetic and health industry was observed. In recent times, prebiotics have been recognized as attractive products due to their higher stability to processing and storage conditions, lower susceptibility to interaction with other compounds in more complex formulation and higher reproducibility of their physiological effects [1]. Consequential rapid growth of market demand brought challenges for biochemical industry, such as requirements to increase production capacity and decrease costs by development of more efficient enzymatic processes and product separation. Majority of prebiotic compounds are classified as oligosaccharides, which can be obtained either by enzymatic synthesis from compounds of lower degree of polymerization (DP) - for example: galacto-oligosaccharides (GOS) from lactose and fructo-oligosaccharides (FOS) from sucrose - or by enzymatic hydrolysis, for example pectic oligosaccharides (POS) from pectin or xylo-oligosaccharides (XOS) from xylan [2]. In both cases, membrane separation is efficient tool for product purification, because OS obtained by synthesis can be separated from lower DP compounds using nanofiltrations, while those obtained by hydrolysis can be separated from compounds of higher DP using ultrafiltration. Hence, it can be expected that selection of adequate membrane material, pore dimensions and downstream processing conditions will have important role in development of novel prebiotic technologies. In this study nanofiltration membrane module was applied with a purpose of purification of FOS obtained in enzymatic synthesis using sucrose as substrate. Two strategies were applied: • purification of reaction mixture obtained after enzymatic synthesis, • simultaneous enzymatic synthesis and purification in nanofiltration membrane module