Optimization of phytase production in solid state fermentation by different fungi

The present study was conducted to explore the potential fungal isolates for maximum production of phytase by optimizing solid substrate preference and growth parameters (pH, temperature, fermentation time) of solid state fermentation (SSF). It has been inferred from the results that all the tested fungi (Aspergillus niger, Aspergillus flavus, Aspergillus versicolor, Aspergillus nidulans, Cladosporium cladosporioides, Trichoderma reesei, and Trichoderma viride) showed inducible expression of phytase. Fungal isolates showed different preference of solid substrate out of wheat bran, lentil, oat, corn and bagasse for maximum production of phytase. Lentil and bagasse were not used preferably by any tested fungi. Among the tested fungi, maximum phytase production was observed in A. flavus (80 U/g of solid substrate) using wheat bran as solid substrate at pH 6 after 7 days of fermentation period at 30°C. It was established that solid substrates with high phytate and low inorganic phosphate (Pi) contents are substrate of choice for phytase production by SSF.   Key words: Phytase, solid state fermentation, optimization.