Thermal characterization of the interaction of poly(3-hydroxybutyrate) with maleic anhydride

Poly(3-hydroxybutyrate), PHB, has been structurally modified with maleic anhydride, MA, in the presence of triethylamine, TEA. Glass transition, melting, and crystallization temperature, obtained from DSC curves, and thermal degradation temperatures obtained from TG ones, were employed to evaluate the influence of the MA proportion on the modification in the PHB chain. According to the results, most of chain modification reactions are the 80/20 and 90/10 proportions. Observations suggest that most chain modification reactions occur when the ratio of PHB/MA is 80/20 or 90/10. This suggests that modifications of PHB in the presence of MA involve main chain scission.

Thermal behavior of the maleic anhydride modified poly(3-hydroxybutyrate)

Poly(3-hydroxybutyrate), PHB has been structurally modified through reaction with maleic anhydride, MA. Transesterification reaction was carried out fixing the PHB and MA and besides time and temperature the concentration of the triethylamine (used as catalyst) was changed. Glass transition, melting and crystallization temperature obtained from DSC curves and thermal degradation temperatures obtained from TG traces were used to evaluate the influence of the reaction conditions on the modification of PHB according to factorial design. on the base of the results the optimum conditions are to perform the PHB modification reaction with MA reaction at 110 degrees C for 1 h with 5% v/v triethylamine.

Characterization of a tannase from Emericela nidulans immobilized on ionic and covalent supports for propyl gallate synthesis

The extracellular tannase from Emericela nidulans was immobilized on different ionic and covalent supports. The derivatives obtained using DEAE-Sepharose and Q-Sepharose were thermally stable from 60 to 75 °C, with a half life (t50) >24 h at 80 °C at pH 5. 0. The glyoxyl-agarose and amino-glyoxyl derivatives showed a thermal stability which was lower than that observed for ionic supports. However, when the stability to pH was considered, the derivatives obtained from covalent supports were more stable than those obtained from ionic supports. DEAE-Sepharose and Q-Sepharose derivatives as well as the free enzyme were stable in 30 and 50 % (v/v) 1-propanol. The CNBr-agarose derivative catalyzed complete tannic acid hydrolysis, whereas the Q-Sepharose derivative catalyzed the transesterification reaction to produce propyl gallate (88 % recovery), which is an important antioxidant. © 2012 Springer Science+Business Media Dordrecht.

Characterization of a glucose- and solvent-tolerant extracellular tannase from Aspergillus phoenicis

Tannases have attracted wider attention because of their biotechnological potential, especially enzymes from filamentous fungi and other microorganisms. However, the biodiversity of these microorganisms has been poorly explored, and few strains were identified for tannase production and characterization. This article describes the production, purification and characterization of a glucose- and solvent-tolerant extracellular tannase from Aspergillus phoenicis. High enzymatic levels were obtained in Khanna medium containing tannic acid up to 72 h at 30 °C under 100 rpm. The purified enzyme with 65% of carbohydrate content had an apparent native molecular mass of 218 kDa with subunits of 120 kDa and 93 kDa and was stable at 50 °C for 1 h. Optima of temperature and pH were 60 °C and 5.0-6.5, respectively. The enzyme was not affected significantly by most ions, detergents and organic solvents. While glucose did not affect the tannase activity, the addition of a high concentration of gallic acid did. The Km values were 1.7 mM (tannic acid), 14.3 mM (methyl-gallate) and 0.6 mM (propyl-gallate). The enzyme was able to catalyze the transesterification reaction to produce propyl-gallate. All biochemical properties suggest the biotechnological potential of the glucose- and solvent-tolerant tannase from A. phoenicis. © 2012 Elsevier B.V. All rights reserved.

Development of a thermoeconomic methodology for optimizing biodiesel production. Part II: Manufacture exergetic cost and biodiesel production cost incorporating carbon credits, a Brazilian case study

The purpose of this study is to carry on a thermoeconomic analysis at a biodiesel production plant considering the irreversibilities in each step (part I: biodiesel plant under study and functional thermoeconomic diagram [1]), making it possible to calculate the thermoeconomic cost in US$/kWh and US$/l of the biodiesel production, and the main byproduct generated, glycerin, incorporating the credits for the CO2 that is not emitted into the atmosphere (carbon credits). Assuming a sale price for both the biodiesel and the byproduct (glycerin), the annual revenue of the total investment in a plant with a capacity of 8000 t/year of biodiesel operating at 8000 h/year was calculated. The variables that directly or indirectly influence the final thermoeconomic cost include total annual biodiesel production, hours of operation, manufacturing exergy cost, molar ratio in the transesterification reaction, reaction temperature and pressure in the process. Depending on the increase or decrease in sale prices for both biodiesel and glycerin, the payback is going to significantly increase or decrease. It is evident that, in exergy terms, the sale of glycerin is of vital importance in order to reduce the biodiesel price, getting a shorter payback period for the plant under study. © 2013 Elsevier Ltd. All rights reserved.

Análise energética do processo experimental de produção de biodiesel a partir de óleo de frango

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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

Sinteses e caracterização de zeólitas para imobilização da lipase de Thermomyces lanuginous aplicada a produção de biodiesel a partir de óleo de palma via rota etílica

Pós-graduação em Microbiologia - IBILCE

Produção de biodiesel etílico com uso de lipases extracelulares de fungos termofílicos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Produção de lipases por fungos termofílicos e mesofílicos e uso na produção de biodiesel etílico

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

Otimização da modificação de cadeia do PHB com anidrido maleico e estudo de comportamento térmico

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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)

Desenvolvimento de metodologias eletroanalíticas para determinação de potássio e fósforo em biodiesel

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de método de determinação de glicerol livre em biodiesel utilizando a técnica de varredura sucessiva de potencial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Polióis de substratos vegetais quimicamente modificados com trimetilolpropano

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)