Purification, characterization and immobilization of urease from Momordica charantia seeds

Ureases are used in beverage, fertilizer and pharmaceutical industries. We report purification, characterization and a simple method for immobilization of urease form Momordica charantia seeds. The purification of the enzyme is a two steps process involving anion exchange chromatography using DEAE-Sepharose matrix followed by size exclusion chromatography. The fold purification of the enzyme was found to be 6.5. The estimated molecular mass and K-m of the enzyme were 174.5 kDa and 34 +/- 0.5 mM, respectively. The purified urease was immobilized on chitosan beads activated with glutaraldehyde. The activation of chitosan beads and immobilization were confirmed by Fourier Transform Infrared (FTIR) spectrometry and Scanning Electron Microscope (SEM), respectively. Moreover, Energy Dispersive X-ray (EDX) analysis shows increased percentage of nitrogen which further confirms immobilization. The efficiency of immobilization was found to be approximately 97%. The immobilized enzyme retains 60% activity till fourteen successive batches of enzymatic reactions which makes it a highly stable product. Comprehensively, the enzyme shows desirable properties for various applications. (C) 2011 Elsevier Ltd. All rights reserved.