Method for directly immobilizing tannase in fermentation liquor

The invention discloses a method for directly immobilizing tannase in fermentation liquor. The method includes (1), fermenting Tie Guanyin tea stems by the aid of aspergillus tubingensis to obtain free crude tannase; (2), utilizing hydrophilic super-paramagnetic nano-particles as carriers for immobilizing free tannase; (3), immobilizing the free tannase on the nano-particles by a direct immobilizing process, a glutaraldehyde cross-linking process and a carbodiimide covalent binding process so as to obtain liquid immobilized tannase; (4), carrying out vacuum freeze-drying on the liquid immobilized tannase to obtain powder immobilized tannase. The aspergillus tubingensis is used as an enzyme producing strain. The method has the advantages that the magnetic nano immobilized tannase is directly immobilized in the fermentation crude enzyme liquor and accordingly can be easily and quickly prepared; the immobilized tannase is excellent in enzyme activity, storage stability, reusability and magnetic control performance.