A tannase that was prepared from Aspergillus niger by a solid-state fermentation on tea byproducts was
investigated to transform the catechins in tea infusion. The tannase could effectively hydrolyze epigallocatechin
gallate (EGCG), gallocatechin gallate (GCG) and epicatechin gallate (ECG) of tea infusion,
which showed pH values ranged from 4.8 to 5.3 during the tannase treatment. T