Conformation studies on Burkholderia cenocepacia lipase via resolution of racemic 1-phenylethanol in non-aqueous medium and its process optimization
•Correlation between enzyme activity/ees and conformation has been investigated.•Enzyme activity variations attributed to secondary/tertiary structure changes.•Fluorescence intensity variations indicated the tertiary structure alterations.•BCL shows a better catalytic efficiency than some other reported lipases.•Better understanding of lipase-catalyzed resolution in non-aqueous media.
In this study, the effect of various organic solvents on enzyme activity and substrate enantiomeric excess (ees) of the lipase from Burkholderia cenocepacia (BCL) was investigated in the enantioselective transesterification of 1-phenylethanol. Secondary structure analysis by Fourier transform-infrared spectroscopy (FT-IR) showed that the variations in secondary structure element content (α-helix, β-sheet, β-turn and random coil) were probably responsible for the changes in enzyme activity and ees. Furthermore, the change in fluorescence intensity indicated, to some extent, the alteration in tertiary structure, which may also explain why organic solvents affect enzyme activity and ees. Moreover, response surface methodology (RSM) was employed to optimize the reaction parameters. The optimized reaction conditions were: substrate molar ratio 4.7:1; reaction time 18.6 h, and reaction temperature 53.4 °C. Under the optimal reaction conditions, the ees and eep were respectively 99.22% and 98.74%, and the corresponding enzyme activity was 1392.2 U/min/g protein. Compared with other lipases, BCL exhibited better catalytic efficiency and has significant potential in industrial applications.
Journal: Process Biochemistry - Volume 48, Issue 12, December 2013, Pages 1905–1913