Physicochemical Aspects of Lipase B from Candida antarctica in Bicontinuous Microemulsions

Abstract

Biotechnology involves applying enzymes in organic synthesis to convert non-natural substrates into enantiomerically pure products under mild reaction conditions. Non-natural substrates are often lipophilic molecules that can hardly be accessed and converted by enzymes in their natural aqueous environment. Bicontinuous microemulsions provide a spongelike nanostructure with a large interfacial area between aqueous and oil domains, which makes them valuable alternative reaction media. In the present study, we introduced lipase B from Candida antarctica into a bicontinuous microemulsion of composition H2O/NaCl-n-octane-pentaethylene glycol monodecylether (C10E5). Phase behavior, partitioning studies, and pulsed-field-gradient NMR measurements revealed that the lipase is mostly adsorbed at the microemulsions interface. Phase diagrams showed a maximum in efficiency with increasing amount of lipase added to the water phase of the microemulsion. It was observed that the ratio between the mass of lipase that is introduced into the system and the mass of lipase that is located at the interface stays constant. Self-diffusion coefficients of all components showed that the presence of the lipase is not influencing the bicontinuity of the microemulsion.

Crystallographic Investigation of Imidazolium Ionic Liquid Effects on Enzyme Structure

“…LipA was targeted in these studies because it is an industrially important enzyme that is used in esterificationa nd transesterification reactions, as well as am odel enzyme for understanding the effects of ILs on enzyme structure. [11][12][13][14][15][16] To understand the molecular basis for the improved stability of QM-lipAa swell as, more generally,the nature of the interaction of ILs with enzymes, we determined the crystal structures of wild-type lipA and QM-lipA in the presenceo fI Ls. Specifically,t he structureso fw ild-type lipA and QM-lipA were solved by soakingc rystals of each enzyme in aqueous solutions with different concentrationsof[ BMIM] [Cl].O fs pecific interest was determining the location and binding modeso ft he cation and anion of the IL in each structure.…”

Hydrolysis of Hydrophobic Esters in a Bicontinuous Microemulsion Catalysed by Lipase B from Candida antarctica

“…This allows counteracting and thus preventing any changes of the phase behaviour, that is, of the microstructure, during the reaction. The influence of CalB on the phase behaviour of the microemulsion system H 2 O/NaCl (CalB)– n ‐octane–C 10 E 5 was published previously and showed that an increase of CalB concentration in the microemulsion system shifts the phase inversion temperature T̃ to lower values and that $\tilde \gamma $ passes a minimum with increasing CalB concentration 16. The phase behaviour of the CalB‐containing microemulsions combined with the partitioning studies revealed that 80–90 % of the CalB molecules are located at the interfacial layer, whereas the rest is located in the water domain of the microemulsion 16.…”

“…The influence of CalB on the phase behaviour of the microemulsion system H 2 O/NaCl (CalB)-n-octane-C 10 E 5 was published previously and showed that an increase of CalB concentration in the microemulsion system shifts the phase inversion temperature T to lower values and that g passes a minimum with increasing CalB concentration. [16] The phase behaviour of the CalB-containing microemulsions combined with the partitioning studies revealed that 80-90 % of the CalB molecules are located at the interfacial layer, whereas the rest is located in the water domain of the microemulsion. [16] In the following, the influence of one substrate and two products on the phase behaviour of microemulsions containing buffer/4 wt % NaCl/p-nitrophenol-n-octane/p-nitrophenyl palmitate/palmitic acid-C 10 E 5 is presented.…”

“…[16] The phase behaviour of the CalB-containing microemulsions combined with the partitioning studies revealed that 80-90 % of the CalB molecules are located at the interfacial layer, whereas the rest is located in the water domain of the microemulsion. [16] In the following, the influence of one substrate and two products on the phase behaviour of microemulsions containing buffer/4 wt % NaCl/p-nitrophenol-n-octane/p-nitrophenyl palmitate/palmitic acid-C 10 E 5 is presented. Note that throughout this work, 100 mm TRIS pH 7 (buffer) is used as an aqueous phase to prepare the microemulsion.…”

Microemulsions with hydrophobic ionic liquids: Influence of the structure of the anion

“…[8] Additionally, the high internal surface of microemulsions mimics the situation at the cell membrane and thus proved to be beneficial for the performance of enzymatic reactions. [9,10] The high solubility of a great variety of compounds in ILs widens the scope for, and gives access to, applications that are not possible with conventional H 2 O -oil microemulsions. So far successful examples of H 2 O -IL microemulsions as reaction media have been found for lactase catalysed reactions [11] and for the preparation of starch nano-particles [12] or porous nano-rods.…”