Carolina de Albuquerque Lima

Federal University of Pernambuco, Arrecife, Pernambuco, Brazil

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Publications (4)7.21 Total impact

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    ABSTRACT: (Production of enzymes by filamentous fungus using sugarcane and sugarcane bagasse as substrate). The production of enzymes by bioprocesses is a good alternative to add value to agroindustrial waste. Sugarcane bagasse, an abundant and cheap by-product of the sugar industry, was tested as a carbon source for the production of biotechnological interesting enzymes. In this work, fungi were isolated from anatomical parts of sugarcane (root, steam and leaf) and, then, were assessed for enzyme production. The isolated and identified fungi were Fusarium sp., Penicillium sp., Trichoderma auroviride and Cladosporium cladosporioides. Trichoderma auroviride was used for enzyme production (xylanase, invertase and protease) using sugarcane as substrate. Xylanase production (2037 U) by Trichoderma auroviride was higher than invertase and protease production; thus, this enzyme was selected for the further studies. The study of the influence of variables (temperature and stirring intensity) on xylanase production by Trichoderma auroviride, using sugarcane bagasse as substrate, showed that the most favorable xylanase production conditions were observed at 25 °C, without stirring intensity and using saline and Tween for enzyme extraction, which led to a 1980 U xylanase activity. Key words: xylanase production, sugarcane bagasse, filamentous fungi, Trichoderma auroviride, enzymes.
    Brazilian Journal of Biosciences. 06/2013; 11(1980-4849):227-234.
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    ABSTRACT: Cow raw milk from dairy cooperatives was examined for its microbial composition. Among the isolates identified, 17.6% were yeasts. The most frequent genus was Candida, although members belonging to the genera Brettanomyces, Dekkera, and Geotricum were also identified. Although qualitative and quantitative tests for extracellular proteolytic activity were positive for all the species isolated, Candida buinensis showed the highest response (23.5 U/mg); therefore, it was selected for subsequent investigation. The results of fermentations carried out at variable temperature, pH, and soybean flour concentration, according to a 2(3) full factorial design, demonstrated that this yeast ensured the highest production of extracellular proteases (573 U/mL) when cultivated at 35 degrees C, pH 6.5, and using soybean flour concentrations in the range 0.1-0.5% (w/v). The cell-free supernatants showed the highest activity at 25 degrees C and pH 7.0, and satisfactory stability in the ranges 25-30 degrees C and pH 7-9. The first-order rate constants of protease inactivation in the cell-free supernatants were calculated at different temperatures from semi-log plots of the residual activity versus time and then used in Arrhenius and Eyring plots to estimate the main thermodynamic parameters of thermoinactivation (E* = 40.0 kJ/mol; DeltaH* = 37.3 kJ/mol; DeltaS* = -197.5 J/mol K; DeltaG* = 101 kJ/mol).
    Applied biochemistry and biotechnology 03/2010; 162(3):830-42. · 1.94 Impact Factor
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    ABSTRACT: Purification of collagenase produced by Penicillium aurantiogriseum URM4622 was carried using a PEG/phosphate aqueous two-phase system (ATPS). A 23-full experimental design was used to investigate the influence of PEG molar mass, PEG concentration and phosphate concentration on the selected responses, namely partition coefficient, activity yield and purification factor. The ATPS was composed of PEG (molar mass of 550, 1500 and 4000 g/mol) at concentrations of 15.0, 17.5 and 20.0% (w/w) and phosphate at concentrations of 12.5, 15.0 and 17.5% (w/w). The best results of one-step extraction of collagenase from the fermentation broth (partition coefficient of 1.01, activity yield of 242% and purification factor of 23.5) were obtained at pH 6.0 using 20.0% (w/w) PEG 550 and 17.5% (w/w) phosphate. The results of this preliminary study demonstrate that the selected ATPS is satisfactorily selective for the extraction of such a collagenase.
    Fluid Phase Equilibria 335:20–25. · 2.38 Impact Factor
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    ABSTRACT: Plant lectins are reversible carbohydrate-binding proteins (or glycoproteins) of non-immune origin that can agglutinate cells or precipitate polysaccharides and glycoconjugates. A polymer/salt aqueous two-phase system (ATPS) based on polyethylene glycol (PEG)/sodium citrate was used for the extraction of lectins from a crude extract (CE) of Cratylia mollis seeds in 24 and 22 previously experimental designs. The effects of pH (4, 5, 6 and 7), PEG molar mass (1500, 4000 and 8000 g/mol), PEG concentration (15, 18.5 and 22% w/w) and citrate concentration (10, 15, 20 and 22% w/w) were analysed to establish the optimal extraction conditions. The optimal performance system consisted of 20% (w/w) citrate and 22% (w/w) PEG 8000 g/mol at pH 5.0 using 20% (w/w) crude extract, which allowed for a 125% activity yield of lectins in the bottom phase, with a purification factor of 13.28. A direct comparison of chromatography and ATPS processes for the recovery of lectin Cramoll 1,4 from the CE revealed a reduction in the number of unit operations (from 10 to 4). An electrophoretic study revealed three bands with molar masses of 30, 16 and 14 kDa, consistent with what has been previously observed for Cramoll 1,4. After purification using ATPS, the lectin was stable until 60 °C, with a decrease in hemagglutinating activity (512–128) at 80 °C. These results indicate that liquid–liquid extraction is an adequate tool for separating and purifying lectins from the CE of C. mollis seeds while maintaining their biological activity, which may have great potential for biotechnological applications.
    Separation and Purification Technology 116:154–161. · 2.89 Impact Factor