Sodium titanate as basic catalyst in transesterification reactions

Sodium titanate was synthesized by the sol-gel method and characterized using X-ray diffraction, thermogravimetry-mass spectrometry, atomic absorption spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis and nitrogen physisorption. The non-calcined material was active as a catalyst in transesterification reactions and showed high stability. An appreciable loss of activity on the fourth reuse was accompanied by the appearance of a new species of oxygen and segregated sodium, identified by X-ray photoelectron spectroscopy (XPS). The XPS spectrum showed that the basic nature of the framework oxygen was inferior to the original basicity, which explained the decline in catalytic activity. (C) 2013 Elsevier Ltd. All rights reserved.

Enzymatic transesterification of soybean oil with ethanol using lipases immobilized on highly crystalline PVA microspheres

Polyvinyl alcohol (PVA) microspheres with different degree of crystallinity were used as solid supports for Rhizomucor miehei lipase immobilization, and the enzyme-PVA complexes were used as biocatalysts for the transesterification of soybean oil to fatty acid ethyl esters (FAEE). The amounts of immobilized enzyme on the polymeric supports were similar for both the amorphous microspheres (PVA4) and the high crystalline microspheres (PVA25). However, the enzymatic activity of the immobilized enzymes was depended on the crystallinity degree of the PVA microspheres: enzymes immobilized on the PVA4 microspheres have shown low enzymatic activity (6.13 U mg-1), in comparison with enzymes immobilized on the high crystalline PVA25 microspheres (149.15 U mg-1). A synergistic effect was observed for the enzyme-PVA25 complex during the transesterification reaction of soybean oil to FAEE: transesterification reactions with free enzyme with the equivalent amount of enzyme that were immobilized onto the PVA25 microspheres (5.4 U) have yielded only 20% of FAEE, reactions with the pure highly crystalline microsphere PVA25 have not yielded FAEE, however reactions with the enzyme-PVA25 complexes have yielded 66.3% of FAEE. This synergistic effect of an immobilized enzyme on a polymeric support has not been observed before for transesterification reaction of triacylglycerides into FAEE. Based on ATR-FTIR, 23Na- and 13C-NMR-MAS spectroscopic data and the interaction of the polymeric network intermolecular hydrogen bonds with the lipases residual amino acids a possible explanation for this synergistic effect is provided. © 2013 Elsevier Ltd. All rights reserved.

Synergistic effect in the catalytic activity of lipase Rhizomucor miehei immobilized on zeolites for the production of biodiesel

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Immobilization of lipases and assay in continuous fixed bed reactor

Lipases are versatile enzymes regarding the range of reactions they catalyse and substrates on which they act. They are as well important as catalyst in organic synthesis. Their immobilization on appropriate supports confer them greater stability besides the possibility of operating in continuous reactors. In order to explore these abilities, the reactions involving hydrolysis of p-nitrophenyl acetate (PNPA) and transesterification of PNPA with n-butanol were chosen. Lipases from two different sources were assayed, namely: microbial (Candida rugosa, CRL, Sigma Type VII) and pancreatic (PPL, Sigma, Type 11). Two immobilization methods were also used, namely: 1) adsorption, using as support the following silica derivatives (150-300μm e 450μ): phenyl, epoxy, amino and without derivation, and 2) covalent binding, using glutaraldehyde as binding agent and silica amino as support. This later method led to better results. Hydrolytic activity was 6.1 U/gsupport for CRL and 0.97U/gsupport for PPL, and of transesterification, 2,8U/gsupport for CRL and 1,9U/gsupport for PPL. Stability of the immobilized enzyme as a function of temperature was evaluated for CRL at 40°C and 50°C and for PPL at 32°C and 40°C. The assays were initially carried out batchwise, both for soluble and immobilized enzymes, aiming to the obtention of parameters for the continues reactor. Lipases immobilized by covalent binding were used in the assays of operacional stability in continuos reactors. For PPL in aqueous medium, at 32°C, and CRL in organic medium at 40°C, both operating continuously, no significant loss of activity was detected along the analysis period of 17 days. In the case of CRL in aqueous medium at 40°C there was a loss of activity around 40% after 18 days. For PPL in organic medium at 40°C the loss was 33% after 20 days. Compairing both sources with each other, very different results were obtained. Higher activitiy was found for CRL, both for hydrolysis and for transesterification reactions, with higher stability in organic medium. PPL showed lower activity as well as higher stability in aqueous medium. The immobilization method by covalent binding showed to be the most appropriate. Immobilized lipases are therefore relatively stable both in aqueous and organic medium.

Heterogeneous catalysis afford biodiesel of babassu, castor oil and blends

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Síntese de sucroésteres derivados de ácidos piridínicos (ácido nicotínico, isonicotínico e pícolínico) e avaliação de suas atividades antimicrobianas

Pós-graduação em Engenharia e Ciência de Alimentos - IBILCE

Sínteses e caracterização de microesferas de poli (álcool vinilico) e sua utilização como suportes para imobilização de lipase produzida por Rhizomucor miehei e seu estudo catalítico na reação de transesterificação do óleo de soja para a produção de biodiesel via rota etílica

Pós-graduação em Microbiologia - IBILCE

Sínteses e caracterização de novos catalisadores zeolíticos e sua como suportes inorgânicos para imobilização de lipase produzida por Rhizomucor miehei e seu estudo catalítico na reação de transesterificação do óleo de soja para produção de biodiesel

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Seleção de fungos termofílicos para produção de lipase e aplicação na produção de biodiesel

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Lipases microbianas: produção, propriedades e aplicações biotecnológicas

Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq)

Nanozeólitas como suportes sólidos para imobilização enzimática: Síntese, caracterização de complexos nanozeólitas/enzimas e sua aplicação como catalisadores heterogêneos para produção de biodiesel via rota etílica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Produção, imobilização e aplicação de lipase de Fusarium verticillioides

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudos experimentais e teórico-computacionais de novos complexos nanozeólitas-enzimas empregados na produção de biocombustíveis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Production and characterization of lipases and immobilization of whole cell of the thermophilic Thermomucor indicae seudaticae N31 for transesterification reaction

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hydroalumination of Thioacetylenes: A Versatile Generation and Reactions of -Aluminate Sulfides Intermediates

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)