Papers by Shirley Furtado
Agrociencia, Dec 1, 2010
ABSTRACT La expansión del cultivo de soja en los últimos años en Uruguay, (Souto, 2010) ha desper... more ABSTRACT La expansión del cultivo de soja en los últimos años en Uruguay, (Souto, 2010) ha despertado el interés de productores familiares por su utilización como alimento para los animales. La presencia en el grano de soja crudo de factores antinutricionales que limitan su utilización digestiva, (Ramos et al., 2006; Bellaver, 2007); hace necesaria la realización de un tratamiento térmico previo a su suministro. El objetivo de este trabajo es evaluar el efecto de diferentes tiempos de cocción en agua de grano de soja sobre la composición química y el grado de inactivación de factores nutricionales.
Enzyme and Microbial Technology, Feb 1, 2007
Crude extracts were partially purified by organic solvents fractionation: best results (96% of pr... more Crude extracts were partially purified by organic solvents fractionation: best results (96% of proteins, 91% of total caseinolytic activity) were obtained by adding four volumes of cold acetone to the crude extract. This preparation (redissolved acetone precipitate, RAP) showed maximum activity (>80%) at pH 5-9, and exhibited high thermal stability (>90% of residual activity after heating for 60 min at 60 • C). The enzyme was completely inhibited by E-64 trans-epoxysuccinyl-leucyl-amido(4-guanidino)-butane and iodoacetic acid and activated by the addition of cysteine or -mercaptoethanol; these results strongly suggest that the isolated protease should be included within the cysteine group, as all the other studied proteases belonging to the family Bromeliaceae. IEF-zymogram of RAP showed five bands (pI 7.3 to <9.3), most of them proteolytically actives, but only three of which (pI 7.6, 8.2 and 8.8) proved to be important. Ion exchange chromatography in DEAE-Sephadex, was selected to separate this active bands.
MRS Advances
ABSTRACTThe use of nanostructured materials for enzyme immobilization is an active field of resea... more ABSTRACTThe use of nanostructured materials for enzyme immobilization is an active field of research due to its large surface area and the new emergent properties derived from its size. The present work is focused on the synthesis of magnetic nanoparticles for the adsorption of cysteine-proteolytic enzymes extracted from Bromelia antiacantha Bertol (Bromeliaceae) fruit. The results show that enzyme adsorption is highly dependent on the temperature and pH. The biocatalyst activity increased up to 40 %, once immobilized onto the magnetic nanoparticles. In addition, they can be recovered using a magnet allowing them to be reused up to 5 cycles with a marginal loss (5 %) of the initial activity.
Process Biochemistry, 2011
Proteolytic biocatalysts extracted from the ripe fruits of Solanum granuloso-leprosum, a native U... more Proteolytic biocatalysts extracted from the ripe fruits of Solanum granuloso-leprosum, a native Uruguayan tree of the Solanaceae family, were stabilized by adsorption onto gamma-alumina supports. Conditions for preparing the biocatalyst-adsorbant system were evaluated for different crude extract (CE) protein concentrations and at different pHs and temperatures. All systems assayed reached equilibrium within 2-4 h. The best proteolytic activity (measured as direct enzymatic activity) was found to be at pH 6.0 and 5 • C. The biocatalyst-adsorbant system was more stable upon storage than the free enzyme in solution, which loses activity over time due to autolytic processes. Stability (resistance to desorption) was studied after ten cycles of incubation at different pHs and temperatures. There was a general tendency to retain higher activity (more than 60%) when the incubation conditions were the same as those used for preparing the biocatalyst-adsorbant system. The best conditions for using this system to treat industrial effluents were evaluated using milk whey from cheese-making and hemoglobin (the main constituent of wastewater from cattle slaughterhouses) as trial substrates.
International Journal of Biotechnology, 2004
... Its hydrolytic action was studied on casein whey and haemoglobin substrates, which represent ... more ... Its hydrolytic action was studied on casein whey and haemoglobin substrates, which represent ecologically contaminating fractions of industrial waste. ... Shirley Furtado is a graduate in Pharmaceutical Chemistry from the Facultad de Química. ...
Preparative Biochemistry & Biotechnology, 2002
Proteolytic biocatalysts were adsorbed and stabilized using alumina as a support medium. Two bioc... more Proteolytic biocatalysts were adsorbed and stabilized using alumina as a support medium. Two biocatalyst-adsorbant systems were prepared with different physical characteristics of the adsorbant: alumina powder and alumina pearls. Direct adsorption onto the support medium has the main advantage, over other fixation methods, that preliminary steps are not required for a good interaction between the support and the biocatalyst. Proteases were adsorbed and stabilized without modifying or sterically hindering their active sites. Parameters affecting adsorption (pH, temperature, ionic strength) were varied so as to optimize adsorption conditions. Operational viability of the immobilized biocatalysts was demonstrated, taking into account the rate of desorption, resistance to microbial attack, and stability during storage. Desorption in water was studied in batch and continuous-flow processes, at various flow rates. The systems also proved to be resistant to microorganisms. Tests for stability during storage found the systems&#39; activity remained constant after 60 days, and they performed better than biocatalysts in solution. Proteolysis of a solution of g per litre of azocasein was carried out in continuous-flow and batch modes, using our biocatalyst-adsorbant systems we prepared. In all cases, free amino group concentrations were around 2.5 times greater after treatment with biocatalyst-adsorbants than they were in the starting solution.
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Papers by Shirley Furtado