%0 Journal Article %T Estudio de la distribuci車n de los tiempos de residencia en un reactor tubular para la hidr車lisis de lecitina de soja con fosfolipasa A2 inmovilizada %A Maroto %A B. %A Camusso %A C. %A Zaritzky %A N. %J Grasas y Aceites %D 2001 %I Consejo Superior de Investigaciones Cient赤ficas %X The hydrolisis of soybean lecithin can be carried out by means of the use of immobilized A2 phospholipase which releases a fatty acid of C-2 position of the phospholipids so that an enriched product in lysolecithins is obtained. The enzymatic reaction follows a first order kinetics when the substrate concentrations are in the range: 6.34a ⊿10-3 M to 19.0a ⊿10-3 M. The value of the rate constant: k= 9.88a ⊿10-2 min-1 corresponds to the one obtained for the immobilized enzyme on alumina. A reactor was constructed and alumina was the selected support because of its good mechanic properties and fundamentally because of its low cost. The flow behaviour in the reactor and how it departs from the ideal model of plug-flow was analyzed by injecting a NaCl solution of a well-known concentration (tracer) and then, passing it through the reactor. According to the experiences carried out, the conductivity measures proved adequate for the determination of the residence times. The system showed lineal behaviour. The residence times in the experimentally built reactor for different load arrangements (particle support + inert load) was analyzed by using three different flows. The nonconverted fractions for the reactor were calculated and differences in the output were observed, in comparison to the plug-flow reactor, precisely because of channelizations and shut-offs that are generated inside the column. Maximal conversion in the experiences carried out both with higher substrate concentrations and for a minor feed flow were achieved. The dispersion module resulted quite higher than the limit that introduces a gaussian curve, for the one for which the degree of supposition of high dispersion was correct. The reactor showed a behaviour similar to that of a reactor of complete mixture and it was concluded that the degree of back-mixing, the formation of whirls and zones of redistribution of material are important. La hidr車lisis de lecitina de soja puede ser efectuada mediante el uso de enzima fosfolipasa A2 inmovilizada, liberando un 芍cido graso de la posici車n C-2 de los fosfol赤pidos para obtener un producto enriquecido en lisolecitinas. La reacci車n enzim芍tica sigue una cin谷tica de primer orden cuando las concentraciones de sustrato est芍n dentro del rango: 6,34 10-3 y 19,0 10-3M. El valor de la constante de velocidad es: k= 9,88 10-2 min-1 cuando la enzima est芍 inmovilizada sobre al迆mina. Se construy車 un reactor que permite la circulaci車n del fluido a trav谷s del soporte. El soporte seleccionado fue al迆mina en consideraci車n a sus buenas propiedades mec芍nicas y a su bajo cos %K A2 phospholipase %K Residence times %K Tubular reactor %K Fosfolipasa A2 %K Reactor tubular %K Tiempo de residencia %U http://grasasyaceites.revistas.csic.es/index.php/grasasyaceites/article/view/371/374