Phytase production by solid state fermentation and enzyme immobilization by spray drying

Abstract

This Project aims the production of fungal phytase and enzyme immobilization by spray drying. In long term, the results of this research will be useful for monogastric animal feed producers. The research will discriminate thermophilic fungi for phytase production, which are deposited in the fungal collection of the Laboratório de Bioquímica e Microbiologia Aplicada of IBILCE/UNESP. These strains were applied successfully for production of other classes of enzymes. The solid state fermentation experiments will be carried out using sugar cane bagasse, orange pulp and peel and wheat bran as solid materials. Initially the temperature will be fixed at 45oC and the moisture content at 70% (w.b.). For the fungus which produces the highest phytase activity, optimization experiments will be carried out having temperature, moisture content and the proportion sugar cane bagasse/orange pulp and peel/wheat bran as the independent variables. Aspergillus niger will be cultivated at 25oC as a reference for phytase production. The raw extract from the fermentation process obtained at the optimal condition will be spray-dryed, having industrial solid by-products as adjuvants. In a first approach, the adjuvants will be discriminated, keeping constant both adjuvant concentration and suspension flow rate, while the air outlet temperature will be varied. For the support that better protected the enzymes, optimization tests will be carried out to assess the best drying condition. Freeze-dried powder will be used as reference for drying quality. The raw extract will be frozen and refrigerated for up to six months, and the inactivation kinetics will be compared with those from the powders dried by spray-drying and freeze-drying. This work presents high potential to produce a product of commercial interest. The groups from the Laboratório de Bioquímica Aplicada e Microbiologia and from Laboratório de Engenharia de Processos e Biorreatores have tradition on supervising MSc and DSc on solid state fermentation for enzyme production and nowadays a MSc dissertation and a research project are on their courses on cellulase immobilization by spray-drying, both supported by FAPESP (2011/02768-0 and 2011/17389-2). This project is bounded to the post-doctoral leave of prof. João Thoméo at the Max Rubner Institut, in Karlsruhe, Germany, during the second semester of 2011, also supported by FAPESP (2011/09726-9). The project dealt with phytase immobilization by spray-drying and was supervised by Dr. Ralf Greiner, an expert on this class of enzymes. Dr. Greiner already agreed on cooperate with the present research. (AU)