A natural consortium, named L1, of Rhodococcus sp. JT-3 and Brevundirnonas sp. JT-9 was obtained from quizalofop-p-ethyl (QE) polluted soil. The consortium was able to use QE as a sole carbon source for growth and degraded 100 mg L-1 of QE in 60 h. Strain JT-3 initiated the catabolism of QE to quizalofop acid (QA), which was used by strain JT-9 as carbon source for growth and to simultaneously feed strain JT-3. A novel esterase EstS-JT, which was responsible for the transformation of QE to QA and essential for the mineralization of QE by the consortium, was cloned from strain JT-3. EstS-JT showed low amino acid identity to other reported esterases from esterase family VIII and represents a new member of this family. The deduced amino acid sequence contained the esterase family VIII conserved motifs S-X-X-K, YSV and WAG. The purified recombinant EstS-JT displayed maximal esterase activity at 35 degrees C and pH 7.5. An inhibitor assay, site-directed mutagenesis and 3D modeling analysis revealed that S-64, K-67 and Y-175 were essential for catalysis and probably comprised the catalytic center of EstS-JT. Additionally, EstS-JT had broad substrate specificity and was capable of hydrolyzing p-nitrophenyl esters (C-2-C-8) and various AOPP herbicides. (C) 2016 Published by Elsevier B.V.