title: Enzyme precipitate coatings of lipase on polymer nanofibers.
abstract: Lipase (LP) was immobilized on electrospun and ethanol-dispersed polystyrene-poly(styrene-co-maleic anhydride) (PS-PSMA) nanofibers (EtOH-NF) in the form of enzyme precipitate coatings (EPCs). LP precipitate coatings (EPCs-LP) were prepared in a three-step process, consisting of covalent attachment, LP precipitation, and crosslinking of precipitated LPs onto the covalently attached LPs via glutaraldehyde treatment. The LP precipitation was performed by adding various concentrations of ammonium sulfate (20-50%, w/v). EPCs-LP improved the LP activity and stability when compared to covalently attached LPs (CA-LP) and the enzyme coatings of LPs (EC-LP) without the LP precipitation. For example, the use of 40% (w/v) ammonium sulfate resulted in EPC40-LP with the highest activity, which was 4.0 and 3.6 times higher than those of CA-LP and EC-LP, respectively. After 165-day incubation under rigorous shaking at 200 rpm, the residual activities of EPC50-LP were 0.5 μM/min mg of EtOH-NF, representing 113 and 75 times higher than those of CA-LP and EC-LP, respectively. When LP was partially purified via a simple ammonium sulfate precipitation and dialysis, both activities and stabilities of EC-LP and EPC-LP could be marginally improved. It is anticipated that the improved LP activity and stability in the form of EPCs would allow for their potential applications in various bioconversion processes such as biodiesel production and ibuprofen resolution.
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Anam 5-ga, Seoungbuk-gu, Seoul, 136-701, Republic of Korea.
authors.forename: Hyo Jin
authors.initials: HJ
authors.lastname: An
authors.forename: Hye-Jin
authors.initials: HJ
authors.lastname: Lee
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Jun
authors.forename: Sang Youn
authors.initials: SY
authors.lastname: Hwang
authors.forename: Byoung Chan
authors.initials: BC
authors.lastname: Kim
authors.forename: Kwanghee
authors.initials: K
authors.lastname: Kim
authors.forename: Kyung-Mi
authors.initials: KM
authors.lastname: Lee
authors.forename: Min-Kyu
authors.initials: MK
authors.lastname: Oh
authors.forename: Jungbae
authors.initials: J
authors.lastname: Kim
mesh_terms: D011232:Chemical Precipitation; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000378:metabolism; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D000431:Ethanol / Q000737:chemistry; D005976:Glutaral / Q000737:chemistry; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D008298:Maleates / Q000737:chemistry; D057139:Nanofibers / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry
chemical_list: D020099:Coated Materials, Biocompatible; D004800:Enzymes, Immobilized; D008298:Maleates; D011108:Polymers; D011137:Polystyrenes; C521900:poly(styrene-co-maleic anhydride); D000431:Ethanol; D008049:Lipase; D005976:Glutaral