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Catalytic potential of a poly(AAc‐ co ‐HPMA‐ cl MBAm)‐matrix‐immobilized lipase from a thermotolerant Pseudomonas aeruginosa MTCC‐4713
Author(s) -
Kanwar Shamsher S.,
Verma Hemant K.,
Kaushal Rajeev K.,
Gupta R.,
Kumar Yogesh,
Chimni Swapandeep S.,
Chauhan Ghansham S.
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.24107
Subject(s) - lipase , hydrolysis , chemistry , nuclear chemistry , catalysis , chromatography , matrix (chemical analysis) , enzyme , organic chemistry
A purified alkaline thermo‐tolerant lipase from Pseudomonas aeruginosa MTCC‐4713 was immobilized on a series of five noble weakly hydrophilic poly(AAc‐ co ‐HPMA‐ cl MBAm) hydrogels. The hydrogel synthesized by copolymerizing acrylic acid and 2‐hydroxy propyl methacrylate in a ratio of 5 : 1 (HG 5:1 matrix) showed maximum binding efficiency for lipase (95.3%, specific activity 1.96 IU mg −1 of protein). The HG 5:1 immobilized lipase was evaluated for its hydrolytic potential towards p ‐NPP by studying the effect of various physical parameters and salt‐ions. The immobilized lipase was highly stable and retained ∼92% of its original hydrolytic activity after fifth cycle of reuse for hydrolysis of p ‐nitrophenyl palmitate at pH 7.5 and temperature 55°C. However, when the effect of pH and temperature was studied on free and bound lipase, the HG 5:1 immobilized lipase exhibited a shift in optima for pH and temperature from pH 7.5 and 55°C to 8.5 and 65°C in free and immobilized lipase, respectively. At 1 m M concentration, Fe 3+ , Hg 2+ , NH 4 + , and Al 3+ ions promoted and Co 2+ ions inhibited the hydrolytic activities of free as well as immobilized lipase. However, exposure of either free or immobilized lipase to any of these ions at 5 m M concentration strongly increased the hydrolysis of p ‐NPP (by ∼3–4 times) in comparison to the biocatalysts not exposed to any of the salt ions. The study concluded that HG 5:1 matrix efficiently immobilized lipase of P. aeruginosa MTCC‐4713, improved the stability of the immobilized biocatalyst towards a higher pH and temperature than the free enzyme and interacted with Fe 3+ , Hg 2+ , NH 4 + , and Al 3+ ions to promote rapid hydrolysis of the substrate ( p ‐NPP). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4252–4259, 2006