Expression， purification and immobilization of recombinant AiiA enzyme onto magnetic nanoparticles.

AiiA is a "28-kDa lactonase" from Gram-positive Bacillus sp. 240B1. The enzyme can hydrolyze and inactivate a variety of acyl homoserine lactones (AHLs)， quorum sensor molecules involve in bacterial quorum sensing (QS). AiiA is a strong candidate for the development of bio-decontaminating agent that can disrupt QS in industrial and environmental samples. However， commercial application of AiiA suffer from several limitations including high cost of production of enzyme and lack of efficient recovery mean(s) of enzyme from the application environment for its reuse. In this study we have cloned， expressed and purified recombinant AiiA (r-AiiA) enzyme. The purified enzyme was covalently immobilized onto magnetic nanoparticles (MNPs) and the quorum quenching ability of r-AiiA-MNP nanobiocatalyst was evaluated in aqueous buffer. Our results show that r-AiiA-MNPs (a) can hydrolyze 3O-C10AHL and inhibit QS in aqueous buffer， (b) can be recovered from the reaction mixture using external magnetic field， and (c) can be reused multiple times to hydrolyze 3O-C10AHL in aqueous buffer. Results of this study can be used to develop a formulation of AiiA enzyme for industrial applications.