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Materials Science and Engineering: B
Vol. 193, 2015, Pages: 217–228

Synthesis and characterization of robust magnetic carriers for bioprocess applications

Willian Kopp, Felipe A. Silva, Lionete N. Lima, Sueli H. Masunaga, Paulo W. Tardioli, Roberto C. Giordano, Fernando M. Ara˙jo-Moreira, Raquel L.C. Giordano

Federal University of São Carlos-UFSCar, Graduate Program in Chemical Engineering, Rodovia Washington Luiz, km 235, São Carlos, São Paulo 13565-905, Brazil.

Abstract

Magnetic carriers are an effective option to withdraw selected target molecules from complex mixtures or to immobilize enzymes. This paper describes the synthesis of robust silica magnetic microparticles (SMMps), particularly designed for applications in bioprocesses. SMMps were synthesized in a micro-emulsion, using sodium silicate as the silica source and superparamagnetic iron oxide nanoparticles as the magnetic core. Thermally resistant particles, with high and accessible surface area, narrow particle size distribution, high saturation magnetization, and with superparamagnetic properties were obtained. Several reaction conditions were tested, yielding materials with saturation magnetization between 45 and 63 emu g-1, particle size between 2 and 200 μm and average diameter between 11.2 and 15.9 μm, surface area between 49 and 103 m2 g-1 and pore diameter between 2 and 60 nm. The performance of SMMps in a bioprocess was evaluated by the immobilization of Pseudomonas fluorescens lipase on to octyl modified SMMp, the biocatalyst obtained was used in the production of butyl butyrate with good results.

Keywords: Silica magnetic microparticles; Bioprocess; Superparamagnetic iron oxide nanoparticles; Sodium silicate; High saturation magnetization.

 
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