Tuning candida rugosa lipasi acylation of polyfunctional templates in SCCO2

Among the enzymes being more largely applied in industrial transformations, lipases find interesting applications in regioselective acylation of polyfunctional compounds. These compounds represent a very interesting class of molecules to be employed as new glucidic drugs and the chemical selective modification of them usually requires several protecting and deprotecting steps, since they have multiple hydroxyl groups of comparable chemical reactivity. Our work was focused on the study of transesterification reactions catalysed by wild type and recombinant microbial lipases by using monoprotected glycosides, as substrates, in organic solvents and in supercritical fluids. It was observed that the reactions in supercritical fluids took place more rapidly and more selectively than in conventional organic solvents

Plant latex lipases: physiological role and applications

Lipases are natural catalysts widely employed to structure various lipids, fats and oils in the cosmetic, pharmaceutical and food industries. Despite their high potential in lipid biotechnology, current application of microbial lipases has been limited owing to high costs and limited availability. During the last two decades, research efforts have been directed towards the identification of low cost and GRAS (Generally Recognized As Safe) lipases sources. Plant lipases from species with oil seeds have been widely studied, though their application has turned out to be disappointing, due to low activity and transient expression during seed germination. In the early nineties, research into in non seed tissues showed high lipolytic activity in the latex of some species of Caricaceae, Euphorbiaceae and Asclepiadaceae. At the moment, crude dried latex from Carica papaya is the most studied biocatalyst in lipid synthesis and modification, but little is known about the physiological role of C. papaya lipase or the applications of other latex lipases. In this paper we report more than ten years of research into the characterisation of plant-latex lipases roles and applications

Isoenzimi lipolitici nel latice di alcune specie del genere Euphorbia

Nell'ambito di alcuni studi sulle lipasi vegetali è stata accertata la presenza di attività lipolitica in alcuni latici del genere Asclepiadacee, Euforbiacee, Caricacee. In particolare gli studi di caratterizzazione delle lipasi da Carica papaya hanno evidenziato la possibilità di impiego di tali enzimi nelle modificazioni di sostanze grasse e lipidi. In tale ambito è stata messa in evidenza la presenza di attività lipolitica nei latici di due generi di Euphorbia sotto forma di isoenzimi di cui ne è stata caratterizzata la specificità di substrato e l'attività lipolitica ed esterasica in diverse condizioni sperimentali. Sono stati inoltre messi a punto protocolli estrattivi e purificativi in fase acquosa delle lipasi da latice che potrebbero fornire le condizioni ottimali per una migliore caratterizzazione biochimica degli enzimi stessi

Procedimento per il controllo delle dimensioni e della morfologia di materiali polimerici nanostrutturati

Procedimento per il controllo delle dimensioni e della morfologia della nanostruttura di almeno un polimero comprendente le fasi di: - esposizione, attraverso una membrana semi-permeabile che consente il trasporto passivo di soluti, di una soluzione del polimero, pre-disciolto in un solvente in grado di disciogliere sostanzialmente in maniera completa il polimero, ad un non-solvente del polimero stesso, in cui il non solvente è miscibile con il solvente; in cui la temperatura, il rapporto v/v solvente/non solvente e la concentrazione del polimero sono selezionate in maniera tale da ottenere in polimero precipitato nella nanostruttura desiderata; - separazione del polimero precipitato dalla soluzion

Method for controlling the dimensions and the morphology of nanostructural polymeric materials, materials thereby obtained and uses thereof

The authors of the present invention have devised a method for controlling the dimensions and the morphology of polymers, that is innovative, simple and low cost. The method provides polymers with different morphology starting from polymers synthesised with any procedure, without the use of emulsifiers. The method exploits a physical barrier, exemplified in dialysis membranes or more in general in semi-permeable membranes that allow the passive transport of solutes, to slow down the mixing of a polymer solution with a non solvent of the polymer itself (the miscibility of the solvent and of the non solvent must be high, preferably complete), in which the dialysis bag containing the solution of the polymer is immersed. As a variant, able further to slow the process, the bag can be immersed in the same solvent present inside, whereto is slowly added the non solvent by dripping (e.g. by means of a peristaltic pump). The gradual mixing of the solvent and of the non solvent inside the bag causes the mixture that is being formed to be progressively less able to solubilise the polymer. The consequent increase in the interface tension pushes the molecules of the polymer to aggregate in spheroidal particles, whose shape allows to minimise the energy of the system, which then form a precipitate. The speed whereat the process takes place is the factor that most influences the morphology of the final product and it is determined by various parameters, among them the solvent – non-solvent pair, the rate of addition of the non solvent to the system and the temperature. The morphology of the particles is then determined by kinetic and thermodynamic factors. From a thermodynamic viewpoint, the most important parameter is the free interface energy. When the precipitation process is slow enough, the morphology is not influenced by the kinetic parameters and the so-called equilibrium morphology is reached, i.e. the one that corresponds to the minimisation of the free energy of the system. With regard to the kinetic parameters, the ones with the greatest influence on particle morphology are: the diffusion and the phase rearrangement inside the particles themselves. The mobility of the polymer chains is restricted during their aggregation and hence phase separation and rearrangement can be slower than the aggregation rate. In this case, kinetic factors prevail over thermodynamic ones and morphologies different from the spherical one are obtained, called non-equilibrium. The spherical morphology, reached when the thermodynamic factors prevail, is the equilibrium morphology]. Control over morphology is easily obtained acting on a few experimental parameters: choice of materials, concentrations, number and type of membranes, temperature. Polymer recovery is total and takes place by centrifuging and subsequent drying

Lipolytic isoenzymes from Euphorbia latex

The activity and substrate specificity of latex lipases from Euphorbia species (E. characias, E. wulfenii, E. pinea, E. myrsinites and E. dendroides) were investigated. High lipolytic activity was found only in E. characias and for the first time in E. wulfenii latex. For both species the lipolytic activity on various triglycerides, and under different temperature and pH conditions, in both crude latex and in partially purified enzymes was quantified. Optimised extraction and purification methods permitted the recovery of the enzymatic fraction with high lipolytic activity. This fraction is probably constituted by a pool of different lipolytic enzymes. Finally, lipolytic activity was also measured for E. characias and E. wulfenii during vegetative and reproductive stages