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  • Author: Wei Du x
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Lipase NS81006 immobilized on Fe3O4 magnetic nanoparticles for biodiesel production

Abstract

Lipase-catalyzed biodiesel production is being the object of extensive research due to the demerits of chemical based catalytic system. Lipase immobilized on Fe3O4 magnetic nanoparticles has the integrated advantages of traditional immobilized lipase and free lipase for its rather fast reaction rate and easy separation. It has been demonstrated that free lipase NS81006 has potential in catalyzing the alcoholysis of renewable oils for biodiesel preparation. In this study, Fe3O4 magnetic nanoparticles functionalized with organosilane compounds like (3-aminopropyl)triethyloxysilane (APTES) and (3-mercaptopropyl)trimethoxysilane) MPTMS were used as carriers for lipase immobilization. Lipase NS81006 was covalently bound to the organosilane-functionalized magnetic nanoparticles by using glutaraldehyde cross-linking reagent. A biodiesel yield of 89% and 81% could be achieved by lipase immobilized on APTES-Fe3O4 and MPTMS-Fe3O4 magnetic nanoparticles respectively under optimized conditions of oil to methanol molar ratio 1:3 with three step addition of methanol, reaction temperature 45°C and reaction time duration 12 h. The lipases immobilized on magnetic nanoparticles could be recovered easily by external magnetic field for further use.

Open access
A Retrospective Study of Continuous Renal Therapy and Anticoagulation in Patients with Hemorrhagic Fever with Renal Syndrome

Abstract

Objective To observe the application of continuous renal replacement therapy (CRRT) and heparin anticoagulation in patients with HFRS, and to explore a more suitable anticoagulant strategy.

Methods Eighty-five severe-type patients (severe group) and 71 critical-type patients (critical group) were enrolled in this study. The frequency of CRRT was compared between the two groups; the frequency of CRRT treated with and without heparin anticoagulation and the frequency of hemorrhage and channel blood clotting induced by the two anticoagulant strategies were observed.

Results The frequency of CRRT in the critical group was higher than that in the severe group (P < 0.001). The frequency of CRRT initiated during the overlapping phases in the critical group was significantly higher than that of the severe group (P = 0.032). The total times of CRRT was 103, and 70 of them were treated with heparin anticoagulation. The frequencies of hemorrhage induced by heparin anticoagulation and no heparinization were 16 and 0, respectively, and the frequencies of channel blood clotting were 2 and 4, respectively.

Conclusions CRRT has been used extensively in the critical-type patients with HFRS. The heparin anticoagulation and no anticoagulant strategies should be used more rationally in patients treated with CRRT, according to the clinical characteristics of the disease.

Open access