In this paper we examined nine strains of filamentous fungi belonging to Aspergillus, Trichoderma and Rhizopus genus for their ability to phytases biosynthesis and accompanying celulase and xylanase enzymes in medium with wheat bran as a soul carbone source. In 8-days submerged fermentations eight strains were able to synthesize phytases and the activity of those enzymes was generally increasing during the process. The most effective producers of phytases were Aspergillus niger KB and Aspergillus niger 551: the activity was 24,45 nkat g^-1 and 17,7 nkat g^-1, respectively. In the experimental conditions not all strains revealed celulase and xylanase activity. In solid state fermentation with A. niger 551 there was observed the important increase of phytases specific activity in comparison to submerged fermentation. The optimum parameters for phytases of A. niger 551 activity were 45 °C and pH 5,6.

17-26