Porcine liver esterase was entrapped in natural polysaccharides K-carrageenan and retention of its activity was determined using p-nitrophenyl acetate as the substrate. The optimum pH for esterase activity of entrapped enzyme showed a little shift towards acidic side. Immobilized enzyme showed improved thermal and storage stability. The entrapped esterase retained 50% of its activity after eight repetitive cycles. Michaelis constant K for the free and entrapped enzymes was almost same indicting no conformational change during immobilization. Maximum velocity V,a, was observed to decrease on immobilization. The free and entrapped esterase was used for selective hydrolysis of methyl 2-acetoxybenzoate to methyl 2-hydroxybenzoate in batch process as well as in a fixed bed reactor. The hydrolysis was observed to be 99% within 2 h for free as well as immobilized enzyme in batch process. The rate of hydrolysis was found to depend on pH. The turn over number of selective hydrolysis in batch and fixed bed reactor was 3.08 x 10(6) and 1.19 x 10(7), respectively. (C) 2008 Wiley Periodicals, Inc.