چکیده (انگلیسی):

Lipases (triacylglycerol acylhydrolase, EC 3.1.1.3) are one of the highest value commercial
enzymes as they have potential applications in biotechnology for detergents, food, pharmaceuticals,
leather, textiles, cosmetics, and paper industries; and are currently receiving considerable
attention because of their potential applications in biotechnology. Bacillus thermocatenulatus Lipase
2 (BTL2) is one of the most important research targets, because of its potential industrial applications.
In this study, the effect of substitution Phe17 with Ser in mutated BTL2 lipase, which conserved
pentapeptide (112Ala-His-Ser-Gln-Gly116) was replaced with similar sequences (207Gly-Glu-
Ser-Ala-Gly211) of Candida rugosa lipase (CLR) at the nucleophilic elbow region. Docking results
confirmed the mutated lipase to be better than the chimeric lipase. So, cloning was conducted,
and the mutated and chimeric btl2 genes were expressed in Escherichia coli, and then the enzymes
were purified by anion exchange chromatography. The mutation increased lipase lipolytic activity
against most of the applied substrates, with the exception of tributyrin when compared with chimeric
lipase. Further, the mutated lipase exhibited higher activity than the chimeric lipase at all temperatures.
Optimum pH of the mutated lipase was obtained at pH 9.5, which was more than the
chimeric one. Enzyme activity of the mutated lipase in the presence of organic solvents, detergents,
and metal ions was also improved than the chimeric lipase.

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