A steady-state fluorescence study of cutinase microencapsulated in AOT reversed micelles at optimal stability conditions

A steady-state fluorescence study of cutinase was performed to evaluate the structure of cutinase in reversed micelles of AOT with the optimised conditions assigned by factorial design. The results obtained by two independent methods are compared. At a W(0) (water to surfactant ratio) value of 2.7, and in the presence of 500 mM hexanol, the fluorescence intensity maximum (lambda(max)) remained almost constant for a period of time longer than 30.5 h and a slight red-shift from 305 to 310 nm was verified changing the W(0) value to 6. Decreasing the amount of hexanol to 100 mM, the changes in lambda(m)ax were more significant, especially for W(0)=6 indicating a noticeable unfolding process. Structural evidence is given reinforcing the role of hexanol as a stabiliser of microencapsulated cutinase and the effect of a drastic reduction in water content.