PRODUCTION OF FRUCTOOLIGOSACCHARIDES BY THE MYCELIA OF ASPERGILLUS-JAPONICUS IMMOBILIZED IN CALCIUM ALGINATE

This work describes fructose oligosaccharide (FOS) production by the i mmobilized mycelia (IM) of a strain of Aspergillus japonicus, isolated from soil. The microorganism was inoculated into 50 mi of medium comp osed of sugar cane molasses (5.0% of total sugars); yeast powder; 2.0% ; K2HPO4, 0.5%; NaNO3, 0.2%; MgSO4. 7H(2)O, 0.05%; KCl, 0.05%, final p H 5.0, and the flasks were agitated in an orbital shaker at 200 rpm fo r 60 h, at 30 degrees C. The beta-fructofuranosidase activity (Uf), tr ansfructosylating activity (Ut), hydrolyzing activity (Uh), and FOS pr oduction were analyzed by high performance liquid chromatography. FOS production was performed in a batch process in a 2-l jar fermenter by IM in calcium alginate beads. The optimum pH and temperature were 5.0- 5.6 and 55 degrees C, respectively No loss of activity was observed wh en the mycelium was maintaned at 60 degrees C for 60 min. Maximum prod uction was obtained using 5.75% (cellular weight/volume) of mycelia (1 22.4 Ut g(-1)) and 65% sucrose solution (w:v) for 4 h of reaction when the final product reached 61.28% of fetal FOS containing GF(2) (30.56 %), GF(3) (26.45%), GF(4) (4.27%), sucrose (9.6%) and glucose (29.10%) . In the assay conditions, 23 batches were performed without loss of a ctivity of the IM, showing that the microorganism and the process util ized have potential for industrial applications. (C) 1998 Elsevier Sci ence Ltd. All rights reserved.