Mixed Reverse Micelles Facilitated Downstream Processing of Lipase Involving Water-Oil-Water Liquid Emulsion Membrane

Our earlier work for the first time demonstrated that liquid emulsion membrane (LEM)
containing reverse micelles could be successfully used for the downstream processing of
lipase from Aspergillus niger. In the present work, we have attempted to increase the extraction
and purification fold of lipase by using mixed reverse micelles (MRM) consisting of cationic
and nonionic surfactants in LEM. It was basically prepared by addition of the internal
aqueous phase solution to the organic phase followed by the redispersion of the emulsion in
the feed phase containing enzyme, which resulted in globules of water-oil-water (WOW)
emulsion for the extraction of lipase. The optimum conditions for maximum lipase recovery
(100%) and purification fold (17.0-fold) were CTAB concentration 0.075 M, Tween 80 concentration
0.012 M, at stirring speed of 500 rpm, contact time 15 min, internal aqueous
phase pH 7, feed pH 9, KCl concentration 1 M, NaCl concentration 0.1 M, and ratio of
membrane emulsion to feed volume 1:1. Incorporation of the nonionic surfactant (e.g.,
Tween 80) resulted in remarkable improvement in the purification fold (3.1–17.0) of the
lipase. LEM containing a mixture of nonionic and cationic surfactants can be successfully
used for the enhancement in the activity recovery and purification fold during downstream
processing of enzymes/proteins.