Pyrethroid-degrading Sphingobium sp JZ-2 and the purification and characterization of a novel pyrethroid hydrolase

A pyrethroid-degrading bacterium strain JZ-2 was isolated from activated sludge treating pyrethroid-manufacturing wastewater. Based on the morphological, physiological and biochemical characterization, and phylogenetic analysis of the 16S rRNA gene sequence, the strain was identified as Sphingobium sp. Strain JZ-2 was capable of degrading fenpropathrin, cypermethrin, permethrin, cyhalothrin, deltamethrin, fenvalerate and bifenthrin. This strain degraded fenpropathrin by hydrolysis of the carboxylester linkage to yield 3-phenoxybenzaldehyde and 2,2,3,3-tetramethylcyclopropanecarboxylic acid. 3-Phenoxybenzaidehyde, 3-phenoxybenzoate, protocatechuate and catechol are the intermediates of fenpropathrin degradation. Protocatechuate and catechol were further oxidized by ortho-cleavage pathway. A novel pyrethroid hydrolase from cell-free extract was purified 108.5-fold to apparent homogeneity with a 10.2% overall recovery It was a monomer with a molecular mass of 31 +/- 1 kDa, a pl of 4.85. The optimal pH and temperature were 7.5 and 40 degrees C, respectively. No cofactors; or coenzymes were required for the pyrethroid-hydrolysis activity. The enzyme was strongly inhibited by many irons (Ag+, Cu2+, Hg2+ and Zn2+), SDS, p-chloromercuribenzoic acid, phenylmethylsulfonyl fluoride and malathion. (C) 2009 Elsevier Ltd. All rights reserved.