Single-Step Production of a Recyclable Nanobiocatalyst for Organophosphate Pesticides Biodegradation Using Functionalized Bacterial Magnetosomes

Abstract

Enzymes are versatile catalysts in laboratories and on an industrial scale; improving their immobilization would be beneficial to broadening their applicability and ensuring their (re)use. Lipid-coated nano-magnets produced by magnetotactic bacteria are suitable for a universally applicable single-step method of enzyme immobilization. By genetically functionalizing the membrane surrounding these magnetite particles with a phosphohydrolase, we engineered an easy-to-purify, robust and recyclable biocatalyst to degrade ethyl-paraoxon, a commonly used pesticide. For this, we genetically fused the opd gene from Flavobacterium sp. ATCC 27551 encoding a paraoxonase to mamC, an abundant protein of the magnetosome membrane in Magnetospirillum magneticum AMB-1. The MamC protein acts as an anchor for the paraoxonase to the magnetosome surface, thus producing magnetic nanoparticles displaying phosphohydrolase activity. Magnetosomes functionalized with Opd were easily recovered from genetically modified AMB-1 cells: after cellular disruption with a French press, the magnetic nanoparticles are purified using a commercially available magnetic separation system. The catalytic properties of the immobilized Opd were measured on ethyl-paraoxon hydrolysis: they are comparable with the purified enzyme, with K m (and k cat) values of 58 µM (and 178 s−1) and 43 µM (and 314 s−1) for the immobilized and purified enzyme respectively. The Opd, a metalloenzyme requiring a zinc cofactor, is thus properly matured in AMB-1. The recycling of the functionalized magnetosomes was investigated and their catalytic activity proved to be stable over repeated use for pesticide degradation. In this study, we demonstrate the easy production of functionalized magnetic nanoparticles with suitably genetically modified magnetotactic bacteria that are efficient as a reusable nanobiocatalyst for pesticides bioremediation in contaminated effluents.

Ecophysiological Response of Rhizophora mangle to the Variation in Hydrochemistry during Five Years along the Coast of Campeche, México

“…In addition, 2011 and 2012 showed severe drought conditions in the Mexican territory. Consequently, 64 of the 174 natural protected areas in Mexico were at risk due to extreme drought [40][41][42][43]. These results may be related to the impacts of ENSO and DPO, climatic phenomena that disrupt the normal intensity, frequency, and duration of storms and hurricanes, droughts, hail, and frosts [44].…”

Generation of Multifunctional Magnetic Nanoparticles with Amplified Catalytic Activities by Genetic Expression of Enzyme Arrays on Bacterial Magnetosomes

“…[1][2][3][4][5] Due to their highly regulated biosynthesis, [6,7] they represent nanoparticles with unique properties, such as high chemical purity and crystallinity, strong magnetization as well as precise morphologies and uniform sizes, which make be employed as scaffolds for the display of multisubunit complexes, [35] and the paraoxonase Opd. [36] However, it still remains unexplored how the activity and stability of enzymes is affected by their magnetosome expression. In addition, potential application (e.g., as magnetic sensors or as bi/multimodal contrast agents) and functionalization of magnetosomes rely on densely decorated, catalytically active particles with maximized protein-to-particle ratios, which has been difficult to achieve by genetic means.…”

Immobilization of the enzyme GpdQ on magnetite nanoparticles for organophosphate pesticide bioremediation

“…Ginet et al functionalized lipid-coated magnetic nanoparticles with a phosphohydrolase for the 6 degradation of the pesticide ethyl-paraoxon; the kinetic properties were comparable to the free enzyme [21]. Dendrimer-modified and plain magnetite nanoparticles (MNPs) have been extensively studied for their potential application in environmental decontamination, medicine and biology [22][23][24][25].…”