Stability of cutinase, wild type and mutants, in AOT reversed micellar system - effect of mixture components of alkyl esters production

BACKGROUND: Fusarium solani pisi cutinase was microencapsulated in reversed micelles of bis(2-ethylhexyl) sodium sulfosuccinate (AOT) in isooctane for the production of alkyl esters, known as biodiesel; its stability in this system was also evaluated. Results using cutinase wild type and three mutants, L153Q, T179C and S54D, were compared. RESULTS: There is a loss of 45% of cutinase wild type activity when incubated in the micellar system for 3 h, indicating a denaturing effect of AOT towards the enzyme, and furthermore a loss of 90% of the activity is observed in the presence of methanol with only 10 min of incubation. In contrast, an improvement of cutinase performance was achieved when incubated with ethanol or butanol, indicating that these alcohols have a protective role regarding the enzyme. Mutant T179C displayed high stability in the presence of methanol with an activity loss of only 16%. CONCLUSIONS: Mutant T179C presented not only high resistance to the denaturing effect of AOT but also high stability in the presence of methanol. This is a promising biocatalyst for a continuous process. (C) 2010 Society of Chemical Industry