Production of fructo-oligosaccharides by Aspergillus ibericus and their chemical characterization

Abstract

A great demand for prebiotics is driving the search for new sources of fructo-oligosaccharides (FOS) producers and for FOS with differentiated functionalities. In the present work, FOS production by a new isolated strain of Aspergillus ibericus was evaluated. The temperature of fermentation and initial pH were optimized in shaken flask to yield a maximal FOS production, through a central composite experimental design. FOS were produced in a one-step bioprocess using the whole cells of the microorganism. The model (R 2 = 0.918) predicted a yield of 0.56, experimentally 0.53 0.03 g FOS .g initial sucrose -1 was obtained (37.0 C and a pH of 6.2). A yield of 0.64 0.02 g FOS .g initial sucrose -1 was obtained in the bioreactor, at 38 h, with a content of 118 4 g.L -1 in FOS and a purity of 56 3%. The chemical structure of the FOS produced by A. ibericus was determined by HPLC and NMR. FOS were identified as 1-kestose, nystose, and 1 F -fructofuranosylnystose. In conclusion, A. ibericus was found to be a good alternative FOS producer.