In situ preparation of magnetic Fe₃O₄-chitosan nanoparticles for lipase immobilization by cross-linking and oxidation in aqueous solution

• Published in: Bioresource technology Vol. 100; no. 14; pp. 3459 - 3464
• Main Authors: Wu, Yue, Wang, Yujun, Luo, Guangsheng, Dai, Youyuan
• Format: Journal Article
• Language: English
• Published: Kidlington [New York, NY]: Elsevier Ltd 01.07.2009; Elsevier
• Subjects: Adsorption; aqueous solutions; Biological and medical sciences; Biotechnology - methods; Chitosan - chemistry; Cross-Linking Reagents - chemistry; crosslinking; enzyme activity; Enzymes, Immobilized - chemistry; Fundamental and applied biological sciences. Psychology; hydrochloric acid; Iron - chemistry; Lipase - chemistry; Magnetics; Metal Nanoparticles - chemistry; methodology; nanoparticles; Nanotechnology - methods; oxidation; Oxygen - chemistry; Polyphosphates - chemistry; Sodium Hydroxide - chemistry; sodium tripolyphosphate; Temperature; triacylglycerol lipase; Water - chemistry; Enzyme; Nanoparticle; In situ; Immobilization; Crosslinking; Lipase; Magnetisation; CS; Nanoparticles; Oxidation; Chitosan; Aqueous solution; Lipolytic enzyme
• DOI: 10.1016/j.biortech.2009.02.018
• ISSN: 0960-8524; 1873-2976

A new and simple method has been proposed to prepare magnetic Fe₃O₄-chitosan (CS) nanoparticles by cross-linking with sodium tripolyphosphate (TPP), precipitation with NaOH and oxidation with O₂ in hydrochloric acid aqueous phase containing CS and Fe(OH)₂, and these magnetic CS nanoparticles were used to immobilize lipase. The effects on the sequence of adding NaOH and TPP, the reaction temperature, and the ratio of CS/Fe(OH)₂ were studied. TEM showed that the diameter of composite nanoparticles was about 80nm, and that the magnetic Fe₃O₄ nanoparticles with a diameter of 20nm were evenly dispersed in the CS materials. Magnetic measurement revealed that the saturated magnetisation of the Fe₃O₄-CS nanoparticles could reach 35.54emu/g. The adsorption capacity of lipase onto nanoparticles could reach 129mg/g; and the maximal enzyme activity was 20.02μmolmin⁻¹ mg⁻¹ (protein), and activity retention was as high as 55.6% at a certain loading amount.