Efficient transformation of phenyl urea herbicide chloroxuron by laccase immobilized on zein polyurethane nanofiber

• Novel zein polyurethane nanofiber (ZPN) for laccase immobilization was developed.
• Glutaraldehyde activation and cross linking maximizes the binding of laccase to ZPN.
• Immobilized laccase (IL) completely transforms chloroxuron in the presence of HoBt.
• Damage to paddy seedlings were minimized when chloroxuron was treated with IL.

Laccases are widely distributed in plants, bacteria, and fungi, and are used for a wide range of applications, including bioremediation. In the present work laccase was immobilized on an electrospun zein polyurethane nanofiber via crosslinking with glutaraldehyde. FESEM and FTIR analysis clearly demonstrates the binding efficiency of laccase on the nanofiber. The relative activity of immobilized laccase was 85% that of free laccase. Immobilized laccase had a better pH and thermal stability than free laccase. The immobilized laccase completely degraded chloroxuron up to 25 reuse cycles in the presence of 1 mM HoBt. Paddy seeds soaked with solution containing chloroxuron treated with immobilized laccase showed a germination percentage closer to the distilled water control; whereas no damage or fatality of paddy seedlings were noticed in treated chloroxuron solution, which demonstrates the ability of immobilized laccase to detoxify the phenyl urea herbicide chloroxuron.

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