A novel multi-enzyme immobilized biocatalyst for Biodegradation of p,p'-DDT

Document Type : Original Article


1 1Soils, Water and Environment Research Institute, Agriculture Research Center, 12619 Giza, Egypt.

2 2Central Laboratory for Environmental Quality Monitoring (CLEQM), Agriculture Research Center, 12619 Giza, Egypt.

3 3 Department of Soils and Water, Faculty of Agriculture, New Valley University- Egypt 3 National Committee of Soil Science, Academy of Scientific Research and Technology- Egypt

4 4 National Water Research Center (NWRC), Cairo, Egypt.


Growing concerns over environmental pollution have necessitated the development of new-generation environmental protection technologies. Multi-enzyme biocatalysts offer a promising approach for reducing pollution caused by organic wastes. However, the recovery of free-form multienzymes is challenging, resulting in high costs and low production efficiency, limiting their application in bioremediation. In this study, we devised a sensitive and stable enzyme biocatalyst by covalently immobilizing multi-enzymes onto nano-silica using glutaraldehyde. Ligninolytic enzymes (laccase, aryl alcohol oxidase, lignin peroxidase, and manganese peroxidase) were produced from Pleurotus ostreatus (NRRL-2366) under submerged fermentation. Enzymes were partially purified through ammonium sulfate precipitation and dialysis. These purified enzymes were immobilized on nano-silica. The resulting immobilized enzymes biocatalyst exhibited stability and activity across a pH range of 4 to 9 and a temperature range of 20 to 55 °C. Immobilization of laccase, lignin peroxidase, manganese peroxidase, and aryl-alcohol oxidase achieved residual activities of 77%, 62.5%, 41.59%, and 28.21%, respectively, after three consecutive batches. Immobilized enzymes biocatalyst effectively degraded p,p'-DDT, and its complete degradation was achieved after incubation at pH 5 and 30 °C for 12 hours, as confirmed by GC-MS analysis. The GC-MS analysis revealed the detection of eleven major metabolites during the degradation process, which were utilized to predict the degradation pathway.


Main Subjects

Articles in Press, Accepted Manuscript
Available Online from 13 June 2024
  • Receive Date: 29 December 2023
  • Revise Date: 22 July 2024
  • Accept Date: 13 June 2024