Production of Inulinase by Fusarium sp. and its Application for Fructooligosaccharide Production for use as Prebiotics

Fructooligosaccharides (FOS) are useful due to their applications in food and pharmaceutical industry. Fusarium spp., isolated from dahlia rhizosphere, produced endoinulinases in a medium containing inulin or sucrose as carbon substrate. Characterisation of exo-inulinase and production of FOS were investigated. Temperature and pH optimum of the enzyme was found to be 60 °C and pH 6.0, respectively. The optimisation of fermentation conditions for inulinase production was carried out using one at a time approach. The optimised medium with sucrose as a carbon source and yeast extract as a nitrogen source were found to be optimal for inulinase production at an initial pH 5.0 and incubation temperature 30 °C for 120 h. Under these conditions, the maximum inulinase concentration of 131.6 U/ml was achieved. SDS PAGE revealed that the molecular weight of the enzyme was around 90 kDa. Further study revealed that Fusarium sp. could produce inulinase as well as invertase. Thin layer chromatography was carried out to analyse the FOS production and their oligomeric properties. Inulin as well FOS can be used as prebiotics as they are selectively fermented by Bifidobacteria and lactic acid bacteria and thus imparting health benefits.