RESUMEN
This work reports experimental kinetic data of solvent-free glycerolysis of olive oil using a commercial immobilized lipase (Novozym 435) under the influence of ultrasound irradiation. The experiments were performed in a mechanically stirred reactor under ultrasound irradiation, evaluating the effects of temperature (50-70 °C), enzyme concentration (2.5-10 wt%) and glycerol to oil molar ratio (0.8:1-3:1). Results show that ultrasound-assisted lipase-catalyzed glycerolysis might be a potential alternative route to conventional methods, as high contents of reaction products, especially monoglycerides, were achieved at mild irradiation power supply (~130 W) and temperature, in a relatively short reaction time (2h) and low enzyme content (7.5 wt%). To completeness, two simplified kinetic modeling approaches, based on the ordered-sequential bi bi mechanism and reaction stoichiometry, were employed to represent the experimental data, thus allowing a better understanding of the reaction kinetics.
Asunto(s)
Glicerol/química , Glicerol/efectos de la radiación , Lipasa/química , Lipasa/efectos de la radiación , Aceites de Plantas/química , Aceites de Plantas/efectos de la radiación , Sonicación/métodos , Activación Enzimática/efectos de la radiación , Enzimas Inmovilizadas , Proteínas Fúngicas , Ondas de Choque de Alta Energía , Cinética , Aceite de Oliva , Dosis de Radiación , Solventes , Especificidad por Sustrato/efectos de la radiaciónRESUMEN
BACKGROUND: This paper reports the catalytic oxidation of the concentrated orange oil phase using the complexes [Fe(III)(BMPP)Cl(micro-O)Fe(III)Cl(3)], [Cu(II)(BTMEA)(2)Cl]Cl and [Co(II)(BMPP)]Cl(2) biomimetic to methane monooxygenase enzyme as catalysts and hydrogen peroxide as oxidant. RESULTS: The reaction products of oil oxidation, mainly nootkatone, were identified by gas chromatography/mass spectrometry. A screening of catalysts was performed through a full 2(3) experimental design, varying the temperature from 30 to 70 degrees C, the catalyst concentration from 7.0 x 10(-4) to 1.5 x 10(-3) mol L(-1) and the oxidant/substrate molar ratio from 1:1 to 3:1. The results of reaction kinetics employing the most promising catalysts showed that conversions to nootkatone of up to 8% were achieved after 16 h at 70 degrees C. CONCLUSION: The results obtained in this study in terms of nootkatone production should be considered encouraging, since a real, industrially collected, raw material, instead of pure valencene, was employed in the reaction experiments, with a final content about ten times that present in the original concentrated oil.
Asunto(s)
Materiales Biomiméticos/química , Complejos de Coordinación/química , Metaloproteínas/química , Oxigenasas/química , Aceites de Plantas/química , Materiales Biomiméticos/síntesis química , Catálisis , Complejos de Coordinación/síntesis química , Cromatografía de Gases y Espectrometría de Masas , Calor , Peróxido de Hidrógeno/química , Cinética , Concentración Osmolar , Oxidantes/química , Oxidación-Reducción , Oxigenasas/metabolismo , Sesquiterpenos Policíclicos , Sesquiterpenos/análisis , Sesquiterpenos/síntesis química , Sesquiterpenos/químicaRESUMEN
This work reports experimental data and kinetic modeling of solvent-free glycerolysis of olive oil using a commercial immobilized lipase (Novozym 435) in the presence of Triton X-100 surfactant for the production of monoacylglycerols (MAG) and diacylglycerols (DAG). The experiments were performed in batch mode evaluating the effects of temperature (30-70 degrees C), enzyme concentration (2.5-18 wt %), Triton X-100 concentration (10-20 wt %), and glycerol to oil molar ratio (3:1, 6:1, and 9:1). Experimental results showed that lipase-catalyzed solvent-free glycerolysis with the addition of Triton X-100 might be a potential alternative route to conventional organic solvent methods, as good conversions were obtained with relatively low enzyme concentrations (9 wt %) in short reaction times (240 min). The glycerolysis and hydrolysis parallel reactions were considered with rate constants estimated by minimizing a maximum likelihood function. A very satisfactory agreement between experimental data and model results was obtained, thus allowing a better understanding of the reaction kinetics.
Asunto(s)
Glicerol/metabolismo , Lipasa/metabolismo , Aceites de Plantas/química , Diglicéridos/metabolismo , Enzimas Inmovilizadas , Glicerol/análisis , Hidrólisis , Cinética , Monoglicéridos/metabolismo , Octoxinol/administración & dosificación , Aceite de Oliva , Aceites de Plantas/análisis , Tensoactivos/administración & dosificaciónRESUMEN
The production of inulinase employing agroindustrial residues as the substrate is a good alternative to reduce production costs and to minimize the environmental impact of disposing these residues in the environment. This study focused on the use of a phenomenological model and an artificial neural network (ANN) to simulate the inulinase production during the batch cultivation of the yeast Kluyveromyces marxianus NRRL Y-7571, employing a medium containing agroindustrial residues such as molasses, corn steep liquor and yeast extract. It was concluded that due to the complexity of the medium composition it was rather difficult to use a phenomenological model with sufficient accuracy. For this reason, an alternative and more cost-effective methodology based on ANN was adopted. The predictive capacity of the ANN was superior to that of the phenomenological model, indicating that the neural network approach could be used as an alternative in the predictive modeling of complex batch cultivations.