Polyphosphazenes as Tunable and Recyclable Supports To Immobilize Alcohol Dehydrogenases and Lipases: Synthesis, Catalytic Activity, and Recycling Efficiency

Abstract

Abstract.The polyphosphazene {NP[O 2 C 12 H 7.5 (NH 2 ) 0.5 ]} n , prepared by reacting {NP[O 2 C 12 H 7.5 (NO 2 ) 0.5 ]} with the Lalancette's reagent, was used for attaching enzymes such as alcohol dehydrogenase (ADH-'A') and lipase (CAL-B). The resulting new biocatalysts exhibited great potential as tunable supports for enzymatic reactions in both aqueous and organic media. The material with immobilized ADH-'A' was as efficient as the commercial enzyme to perform stereoselective bioreductions of ketones in aqueous solutions and could be used for the reduction of various aliphatic and aromatic ketones up to 60ºC and recycled several times without significant loss of activity even after three months of storage. The biocatalyst obtained with CAL-B was more efficient than the free enzyme for kinetic resolutions in organic solvents and exhibited a moderately good capability of reutilization.2

Immobilized redox enzymatic catalysts: Baeyer–Villiger monooxygenases supported on polyphosphazenes

“…Initially, amino polyphosphazene 5 was activated employing glutaraldehyde due to the fact that this molecule posses two reactive aldehydes moieties, being a logical choice to act as linker between the polymer and the protein. In the same conditions as previously shown [18], polyphosphazene with glutaraldehyde 8 was obtained in high yields. In the following step, we tried to link PAMO (polymer 11, Scheme 2) in the same conditions that were found for ADH-A.…”

“…1 unit (U) of PAMO oxidizes 1.0 μmol of phenylacetone to benzyl acetate per minute at pH 9.0 and 25 ºC in the presence of NADPH. Polyphosphazenes 1 [38,39], 2-4 [40], and 5 [18] were synthesized as previously described. Tetrahydrofuran (THF) was treated with KOH and distilled twice from Na in the presence of benzophenone.…”

“…Due to our previous experience with polymer 5 [18], we started the study with this carrier. Thus, it was envisaged to use the same covalent methodology in view of the excellent results obtained for ADH-A and CAL-B.…”

“…The polyphosphazene {NP[O 2 C 12 H 7.5 (NH 2 ) 0.5 ]} n was prepared by a nitration-reduction sequence and was successfully employed as carrier to attach Candida antarctica lipase B and alcohol dehydrogenase from Rhodococcus ruber (ADH-A). Using these supports we could demonstrate that the immobilized lipase was stable in organic solvents while the immobilized alcohol dehydrogenase (ADH) was used in aqueous solution [18]. These biocatalysts could be recycled several times in both aqueous and organic media.…”

Electroanalytical Analysis of Glassy Carbon Electrode Modified With Cooh- And No2- Functionalized Polyspyrophosphazenes

“…Recently was reported the synthesis of NO 2 −functionalized polyspyrophosphazenes, where the regioselective and controlled direct nitration of the homopolymer [NP(O 2 C 12 H 8 )] n , [4] was achieved by taking advantage of the unusual high solubility and stability of the precursor in concentrated sulfuric acid, to obtain in one-pot {NP[O 2 C 12 H 8- (2), with x between 0.2 and 2 with excellent yields [5]. The NH 2 −functionalized polyspyrophosphazenes have been prepared by reduction of mono and dinitrated polymers with the Lalancette´s reagent and have been proposed as tunable and recyclable supports to immobilize alcohol dehydrogenases and lipases [6,7]. The polyphosphazenes are a versatile class of polymers with interesting chemical and physical properties depending on the attached groups in the backbone to produce a spectacular array of materials with diverse properties and applications [8, 9, 10, 11].…”