A novel feruloyl esterase from a soil metagenomic library with tannase activity

A gene (tan410) encoding a feruloyl esterase was isolated by screening a cotton soil metagenomic library. Sequence analysis revealed that tan410 encodes a protein of 520 amino acids with a predicted molecular weight of 55 kDa. The gene was further expressed in Escherichia coli BL21 (DE3) using a pET expression system. The recombinant enzyme was purified and characterized. Its optimum temperature and pH were 35 °C and 7.0, respectively. Tan410 activity was enhanced by the addition of Mn2+, Mg2+, NH4+ and Ni2+. Besides ethyl ferulate, methyl caffeate, and methyl p-coumarate, Tan410 can also hydrolyze methyl gallate, tannic acid, epicatechin gallate, and epigallocatechin gallate which makes Tan410 an interesting enzyme for biotechnological applications.