A novel organophosphate hydrolase from Arthrobacter sp. HM01: Characterization and applications

• Published in: Bioresource technology 2022-04, Vol.349, p.126870-126870, Article 126870
• Main Authors: Mali, Himanshu, Shah, Chandni, Rudakiya, Darshan M., Patel, Darshan H., Trivedi, Ujjval, Subramanian, R.B.
• Format: Article
• Language: English
• Subjects: Arthrobacter - genetics; Arthrobacter - metabolism; Bioremediation; Chemical warfare agents; Organophosphorus; Organophosphorus Compounds - metabolism; Pesticides; Pesticides - chemistry; Phosphoric Monoester Hydrolases - chemistry; Phosphoric Monoester Hydrolases - genetics; Phosphotriesterase; Piperidines; Site-directed mutagenesis
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2022.126870

[Display omitted] •Organophosphates (OPs) pesticides are emerging environmental pollutants.•A novel recombinant OPs hydrolase biocatalytic system (ropdH) was investigated.•ropdH enzyme was functionally characterized to improve its catalytic properties.•The active site of the ropdH enzyme was determined by site-directed mutagenesis.•Several OPs pesticides were degraded by ropdH and a degradation pattern was proposed. Bioremediation systems coupled to efficient microbial enzymes have emerged as an attractive approach for the in-situ removal of hazardous organophosphates (OPs) pesticides from the polluted environment. However, the role of engineered enzymes in OPs-degradation is rarely studied. In this study, the potential OPs-hydrolase (opdH) gene (Arthrobacter sp. HM01) was isolated, cloned, expressed, and purified. The recombinant organophosphate hydrolase (ropdH) was ∼29 kDa; which catalyzed a broad-range of OPs-pesticides in organic-solvent (∼99 % in 30 min), and was found to increase the catalytic efficiency by 10-folds over the native enzyme (kcat/Km: 107 M−1s−1). The degraded metabolites were analyzed using HPLC/GCMS. Through site-directed mutagenesis, it was confirmed that, conserved metal-bridged residue (Lys-127), plays a crucial role in OPs-degradation, which shows ∼18-folds decline in OPs-degradation. Furthermore, the catalytic activity and its stability has been enhanced by >2.0-fold through biochemical optimization. Thus, the study suggests that ropdH has all the required properties for OPs bioremediation.