Cloning, expression, and characterization of polyamidase from Nocardia farcinica and its application to polyamide modification.

Polyamidase was able to hydrolyze the amide bond of insoluble polymer. In the present study, a polyamidase from Nocardia farcinica CGMCCC4.1166 was cloned and expressed in E. coli BL21(DE3). The recombinant polyamidase was purified to homogeneity, through a combination of chromatography of anion exchange, and hydrophobic interaction. The purified enzyme was characterized in detail. The optimum temperature of the enzyme was 50°C, and it was stable below 40°C. The enzyme had an optimum pH of 8.0, with pH stability between pH 7.0 and 9.0. The enzyme does not need metal ion as cofactor. In addition, when the enzyme was utilized to hydrolyze polyamide, the monomeric product of adipic acid was verified by HPLC analysis; as well, the wettability and dyeability of polyamide fabric after enzyme treatment were significantly improved, which differed from those of its inactive S173A mutant, and the amidase from Rhodococcus pyridinivorans. Furthermore, the structural features near the active site of polyamidase, different from other amidases, were explored. [ABSTRACT FROM AUTHOR]