Enhancement of Ethyl Propionate Synthesis by poly (AAc-co-HPMA-cl-MBAm)-immobilized  Pseudomonas aeruginosa MTCC-4713, Exposed to Hg2+ and NH4+ Ions

Kanwar, S. S. and Verma, H. K. and Pathak, S. and Kaushal, R. K. and Kumar, Y. and Verma, M. L. and Chimni, S. S. and Chauhan, G. S. (2006) Enhancement of Ethyl Propionate Synthesis by poly (AAc-co-HPMA-cl-MBAm)-immobilized  Pseudomonas aeruginosa MTCC-4713, Exposed to Hg2+ and NH4+ Ions. Acta Microbiologica et Immunologica Hungarica, 53 (2). pp. 195-207. ISSN 1217-8950

Text amicr.53.2006.2.6.pdf Restricted to Repository staff only until 30 June 2026. Download (92kB)

Abstract

A purified alkaline thermo-tolerant bacterial lipase from Pseudomonas aeruginosa MTCC-4713 was immobilized on a poly (AAc-co-HPMA-cl-MBAm) hydrogel. The hydrogel-bound lipase achieved 93.6% esterification of ethanol and propionic acid (300 mM: 100 mM) into ethyl propionate at temperature 65oC in 3 h in the presence of a molecular sieve (3 Å). In contrast, hydrogel-immobilized lipase pre-exposed to 5 mM of HgCl2 or NH4Cl resulted in approximately 97% conversion of reactants in 3 h into ethyl propionate under identical conditions. The salt-exposed hydrogel was relatively more efficient in repetitive esterification than the hydrogel- bound lipase not exposed to any of the cations. Moreover, bound lipase exposed Hg2+ or NH4+ ions showed altered specificity towards p-nitrophenyl esters and was more hydrolytic towards higher C-chain p-nitrophenyl esters (p-nitrophenyl laurate and p-nitrophenyl palmitate with C 12 and C 16 chain) than the immobilized lipase not exposed to any of the salts. The later showed greater specificity towards p-nitrophenyl caprylate (C 8).

Actions (login required)

Edit Item