title: A proposed mechanism for detergent-assisted foam fractionation of lysozyme and cellulase restored with beta-cyclodextrin.
abstract: Foam fractionation by itself cannot effectively concentrate hydrophilic proteins such as lysozyme and cellulase. However, the addition of a detergent to a protein solution can increase the foam volume, and thus, the performance of the foam fractionation process. In this article, we propose a possible protein concentration mechanism of this detergent-assisted foam fractionation: A detergent binds to an oppositely charged protein, followed by the detergent-protein complex being adsorbed onto a bubble during aeration. The formation of this complex is inferred by a decrease in surface tension of the detergent-protein solution. The surface tension of a solution with the complex is lower than the surface tension of a protein or a detergent solution alone. The detergent can then be stripped from the adsorbed protein, such as cellulase, by an artificial chaperone such as beta-cyclodextrin. Stripping the detergent from the protein allows the protein to return to its original conformation and to potentially retain all of its original activity following the foam fractionation process. Low-cost alternatives to beta-cyclodextrin such as corn dextrin were tested experimentally to restore the protein activity through detergent stripping, but without success.
authors.affiliation: Chemical Engineering Department, Vanderbilt University, Nashville, TN 37235, USA.
authors.forename: Vorakan
authors.initials: V
authors.lastname: Burapatana
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Booth
authors.forename: Ian M
authors.initials: IM
authors.lastname: Snyder
authors.forename: Ales
authors.initials: A
authors.lastname: Prokop
authors.forename: Robert D
authors.initials: RD
authors.lastname: Tanner
mesh_terms: D002480:Cellulase / Q000737:chemistry* / Q000302:isolation & purification*; D005591:Chemical Fractionation / Q000379:methods*; D003902:Detergents / Q000737:chemistry*; D005240:Feasibility Studies; D005740:Gases / Q000737:chemistry; D009113:Muramidase / Q000302:isolation & purification*; D013500:Surface Tension; D047392:beta-Cyclodextrins / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D003902:Detergents; D005740:Gases; D047392:beta-Cyclodextrins; D009113:Muramidase; D002480:Cellulase; C031215:betadex