EFFECT OF MUTATION IN NONCONSENSUS SEQUENCE THR-X-SER-X-GLY OF CANDIDA-ANTARCTICA LIPASE-B ON LIPASE SPECIFICITY, SPECIFIC ACTIVITY AND THERMOSTABILITY

Non-consensus residue threonine in Candida antarctica B lipase was exc hanged with glycine residue using site specific mutation. The effect o f the mutation on the thermostability was investigated by measuring re sidual activity after heat treatment of the lipase and the mutant. A s ignificant increase in thermostability was found for the mutant lipase . Specific activity of the mutant lipase was determined using tributyr in as substrate which showed a twofold decrease in specific activity. To investigate the effect of mutation on the specificity and activity in ester synthesis, both the mutant lipase and the native lipases were immobilized on a solid support. Ester synthesis using decanol as alco hol with three different fatty acids was carried out. The activity and specificity of the mutant lipase was unaltered in the ester synthesis as compared with the native lipase.