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Search Results: 1 - 10 of 327196 matches for " Cristiane S. Farinas "
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Canola Cake as a Potential Substrate for Proteolytic Enzymes Production by a Selected Strain of Aspergillus oryzae: Selection of Process Conditions and Product Characterization
Adriana C. Freitas,Ruann J. S. Castro,Maria A. Fontenele,Antonio S. Egito,Cristiane S. Farinas,Gustavo A. S. Pinto
ISRN Microbiology , 2013, DOI: 10.1155/2013/369082
Abstract: Oil cakes have excellent nutritional value and offer considerable potential for use in biotechnological processes that employ solid-state fermentation (SSF) for the production of high value products. This work evaluates the feasibility of using canola cake as a substrate for protease production by a selected strain of Aspergillus oryzae cultivated under SSF. The influences of the following process parameters were considered: initial substrate moisture content, incubation temperature, inoculum size, and pH of the buffer used for protease extraction and activity analysis. Maximum protease activity was obtained after cultivating Aspergillus oryzae CCBP 001 at 20°C, using an inoculum size of 107?spores/g in canola cake medium moistened with 40?mL of water to 100?g of cake. Cultivation and extraction under selected conditions increased protease activity 5.8-fold, compared to the initial conditions. Zymogram analysis of the enzymatic extract showed that the protease molecular weights varied between 31 and 200?kDa. The concentrated protease extract induced clotting of casein in 5?min. The results demonstrate the potential application of canola cake for protease production under SSF and contribute to the technological advances needed to increase the efficiency of processes designed to add value to agroindustrial wastes. 1. Introduction Proteases are one of the three largest groups of industrial enzymes and have a wide range of applications in the food, textile, and pharmaceutical industries [1]. Sources of proteases include plants, animals, and microorganisms. However, proteases from plant and animal sources are unable to meet global demand, as a result of which there is a need to develop efficient processes for microbial protease production. In fact, of the hundreds of enzymes currently used industrially, over half are derived from fungi and more than one-third from bacteria, with the remainder originating from animal (8%) and plant (4%) sources [2]. Microbial proteases account for approximately 40% of total worldwide sales of enzymes [3]. Processes that can be used for microbial protease production include submerged fermentation (SmF) and solid-state fermentation (SSF). The latter is particularly advantageous for enzyme production by filamentous fungi, since it simulates the natural habitat of these microorganisms [4, 5]. Another advantage of SSF is that agroindustrial wastes (oil cakes, bagasse, wheat bran, etc.) can be used as the solid substrate, acting as sources of both carbon and energy. However, certain operational limitations of SSF, such as
Production of Biomass-Degrading Multienzyme Complexes under Solid-State Fermentation of Soybean Meal Using a Bioreactor
Gabriela L. Vitcosque,Rafael F. Fonseca,Ursula Fabiola Rodríguez-Zú?iga,Victor Bertucci Neto,Sonia Couri,Cristiane S. Farinas
Enzyme Research , 2012, DOI: 10.1155/2012/248983
Abstract: Biomass-degrading enzymes are one of the most costly inputs affecting the economic viability of the biochemical route for biomass conversion into biofuels. This work evaluates the effects of operational conditions on biomass-degrading multienzyme production by a selected strain of Aspergillus niger. The fungus was cultivated under solid-state fermentation (SSF) of soybean meal, using an instrumented lab-scale bioreactor equipped with an on-line automated monitoring and control system. The effects of air flow rate, inlet air relative humidity, and initial substrate moisture content on multienzyme (FPase, endoglucanase, and xylanase) production were evaluated using a statistical design methodology. Highest production of FPase (0.55?IU/g), endoglucanase (35.1?IU/g), and xylanase (47.7?IU/g) was achieved using an initial substrate moisture content of 84%, an inlet air humidity of 70%, and a flow rate of 24?mL/min. The enzymatic complex was then used to hydrolyze a lignocellulosic biomass, releasing 4.4?g/L of glucose after 36 hours of saccharification of 50?g/L pretreated sugar cane bagasse. These results demonstrate the potential application of enzymes produced under SSF, thus contributing to generate the necessary technological advances to increase the efficiency of the use of biomass as a renewable energy source. 1. Introduction Biomass-degrading enzymes are one of the most costly inputs affecting the economic viability of the biochemical route for biomass conversion into biofuels. This is due to the large scale of the processes involved in biofuel production, and the considerable quantities of enzymes that are required. In addition to quantity, the quality of the enzymatic complex is an important issue, since a cocktail containing cellulases, hemicellulases, pectinases, and other accessory enzymes, acting in synergy in the degradation process, is necessary due to the high recalcitrance of plant biomass. This enzymatic complex is produced by a wide variety of microorganisms (bacteria and fungi); however, the aerobic fungi are known for their higher growth and protein secretion rates [1, 2]. Most commercial cellulases are produced by filamentous fungi of the genera Trichoderma and Aspergillus [3]. The use of solid-state fermentation (SSF) is particularly advantageous for enzyme production by filamentous fungi, since it simulates the natural habitat of the microorganisms [4]. From the environmental point of view, the main benefit of SSF is the ability to use agroindustrial waste (sugarcane bagasse, wheat bran, soybean meal, etc.) as a solid substrate that
Correlation between Agar Plate Screening and Solid-State Fermentation for the Prediction of Cellulase Production by Trichoderma Strains
Camila Florencio,Sonia Couri,Cristiane Sanchez Farinas
Enzyme Research , 2012, DOI: 10.1155/2012/793708
Abstract: The viability of converting biomass into biofuels and chemicals still requires further development towards the reduction of the enzyme production costs. Thus, there is a growing demand for the development of efficient procedures for selection of cellulase-producing microorganisms. This work correlates qualitative screening using agar plate assays with quantitative measurements of cellulase production during cultivation under solid-state fermentation (SSF). The initial screening step consisted of observation of the growth of 78 preselected strains of the genus Trichoderma on plates, using microcrystalline cellulose as carbon source. The 49 strains that were able to grow on this substrate were then subjected to a second screening step using the Congo red test. From this test it was possible to select 10 strains that presented the highest enzymatic indices (EI), with values ranging from 1.51 to 1.90. SSF cultivations using sugarcane bagasse and wheat bran as substrates were performed using selected strains. The CG 104NH strain presented the highest EGase activity (25.93?UI·g?1). The EI results obtained in the screening procedure using plates were compared with cellulase production under SSF. A correlation coefficient ( ) of 0.977 was obtained between the Congo red test and SSF, demonstrating that the two methodologies were in good agreement. 1. Introduction Cellulolytic microorganisms play an important role in the biosphere by recycling cellulose, the most abundant renewable carbohydrate produced by plants through the mechanism of photosynthesis [1]. In order to perform this task, these microorganisms have evolved a variety of strategies to attack the cell wall components, and therefore possess a comprehensive enzymatic arsenal that is able to degrade plant biomass. These enzymatic cocktails are often optimized according to the substrate and contain a mixture of cellulases, hemicellulases, pectinases, ligninases, and other accessory enzymes that act synchronously and synergistically in the degradation process [2]. Given the advantages of the enzymatic route in the bioconversion of biomass into fuels, there is an increasing demand for more effective enzymatic cocktails that could help to reduce the costs of cellulosic ethanol production. Among a large number of nonpathogenic microorganisms capable of producing useful enzymes, filamentous fungi are particularly interesting due to their high production of extracellular enzymes [3]. Members of the Trichoderma genus are especially notable for their high enzymatic productivity. Around 100 different Trichoderma
Orbital Zeeman effect: Signature of a massive spin wave mode in ferromagnetism
Paulo F. Farinas,Kevin S. Bedell
Physics , 2002,
Abstract: By deriving the quantum hydrodynamic equations for an isotropic single-band ferromagnet in an arbitrary magnetic field, we find that a massive mode recently predicted splits under the action of the field. The splitting is a peculiarity of charged fermions and is linear in the field to leading order in $q$ bearing resemblance to the Zeeman effect in this limit, and providing a clear signature for the experimental observation of this mode.
Recombinant human proinsulin from transgenic corn endosperm: solvent screening and extraction studies
Farinas, C. S.;Leite, A.;Miranda, E. A.;
Brazilian Journal of Chemical Engineering , 2007, DOI: 10.1590/S0104-66322007000300002
Abstract: recombinant pharmaceutical proteins are being produced in different systems such as bacteria and mammalian cell cultures. the use of transgenic plants as bioreactors has recently arisen as an alternative system offering many practical and economic advantages. however, finding an optimum strategy for the downstream processing (dsp) of recombinant proteins from plants still remains a challenge. in this work, we studied the extraction of recombinant human proinsulin (rhproinsulin) produced in the endosperm of transgenic corn seeds. an efficient extraction solvent was selected and the effects of temperature, solvent-to-solid ratio, time, and impeller rotational speed on the extraction were evaluated using an experimental design. after an extraction kinetics study, temperature was further evaluated to maximize rhproinsulin concentration in the extracts and to minimize the native corn components carbohydrates, phenolic compounds, and proteins. a high efficiency condition for extracting rhproinsulin with the selected solvent - 50 mm sodium bicarbonate buffer ph 10.0 and 5 mm dtt - was an extraction time of 2 h at a solvent-to-solid ratio of 10:1 and 25o c. the maximum rhproinsulin concentration in the extracts at that condition was 18.87 mg l-1 or 0.42% of the total soluble protein. these values are within the range in which the production of pharmaceutical proteins in plants can be competitive with other expression systems. the results presented provide information for the development of an additional production platform for the hormone insulin.
The 'Higgs' amplitude mode in weak ferromagnetic metals
Yi Zhang,Paulo F. Farinas,Kevin S. Bedell
Physics , 2013,
Abstract: Using Ferromagnetic Fermi liquid theory, Bedell and Blagoev derived the collective low-energy excitations of a weak ferromagnet. They obtained the well-known magnon (Nambu-Goldstone) mode and found a new gapped mode that was never studied in weak ferromagnetic metals. In this article we have identified this mode as the Higgs boson (amplitude mode) of a ferromagnetic metal. This is identified as the Higgs since it can be show that it corresponds to a fluctuation of the amplitude of the order parameter. We use this model to describe the itinerant-electron ferromagnetic material MnSi. By fitting the model with the existing experimental results, we calculate the dynamical structure function and see well-defined peaks contributed from the magnon and the Higgs. Our estimates of the relative intensity of the Higgs amplitude mode suggest that it can be seen in neutron scattering experiments on MnSi.
Hidden spin-current conservation in 2d Fermi liquids
Paulo F. Farinas,Kevin S. Bedell,Nelson Studart
Physics , 1998, DOI: 10.1103/PhysRevLett.82.3851
Abstract: We report the existence of regimes of the two dimensional Fermi liquid that show unusual conservation of the spin current and may be tuned by varying some parameter like the density of fermions. We show that for reasonable models of the effective interaction the spin current may be conserved in general in 2d, not only for a particular regime. Low temperature spin waves propagate distinctively in these regimes and entirely new ``spin-acoustic'' modes are predicted for scattering-dominated temperature ranges. These new high-temperature propagating spin waves provide a clear signature for the experimental search of such regimes.
Produ??o de celulases por Aspergillus niger por fermenta??o em estado sólido
Rodríguez-Zú?iga, Ursula Fabiola;Farinas, Cristiane Sanchez;Bertucci Neto, Victor;Couri, Sonia;Crestana, Silvio;
Pesquisa Agropecuária Brasileira , 2011, DOI: 10.1590/S0100-204X2011000800018
Abstract: the objective of this work was to evaluate cellulase enzyme production by the filamentous fungus aspergillus niger by solid-state fermentation of different substrates. the solid substrates sugarcane bagasse, wheat bran, soybean meal, and their mixtures were evaluated. the effects of substrate moisture contents (60, 70, and 80% in humid basis) and of the supplementation with culture media: sucrose, basic mandels & weber, modified mandels & weber, with the addition of carboxymethyl cellulose, and czapeck dox, were evaluated in substrate with 90% bagasse and 10% soybean meal. the highest total cellulose and endoglucanase activities, in wheat bran, were obtained after 72 hours: 0.4 and 21.0 iu g-1, respectively. there was an expressive increase in enzymatic activities as the proportion of bran in the substrate increased, in comparison to fermentation with sugarcane bagasse only. the 50% moisture content was insufficient to fully hydrate sugarcane bagasse, and the ideal humidity varies according to the medium used for supplementation and is between 70 and 80%. the modified mandels &weber medium shows the best result as an inductor of enzymatic activity.
Evaluation of operational parameters on the precipitation of endoglucanase and xylanase produced by solid state fermentation of Aspergillus niger
Farinas, C. S.;Scarpelini, L. M.;Miranda, E. A.;Bertucci Neto, V.;
Brazilian Journal of Chemical Engineering , 2011, DOI: 10.1590/S0104-66322011000100003
Abstract: in order to develop cost effective processes for converting biomass into biofuels, it is essential to improve enzyme production yields, stability and specific activity. in this context, the aim of this work was to evaluate the concentration of two enzymes involved in the hydrolysis of biomass, endoglucanase and xylanase, through precipitation. statistical experimental design was used to evaluate the influence of precipitant agent concentration (ammonium sulfate and ethanol), aging time, and temperature on enzyme activity recovery. precipitant agent concentration and aging time showed a statistically significant effect at the 95% confidence level, on both enzyme activity recoveries. the recovery of endoglucanase with ammonium sulfate and ethanol reached values up to 65 and 61%, respectively. for xylanase, the recovery rates were lower, 27 and 25% with ammonium sulfate and ethanol, respectively. the results obtained allowed the selection of the variables relevant to improving enzyme activity recovery within operational conditions suitable for industrial applications.
Contracep??o e gravidez na adolescência na perspectiva de jovens pais de uma comunidade favelada do Rio de Janeiro
Cabral, Cristiane S.;
Cadernos de Saúde Pública , 2003, DOI: 10.1590/S0102-311X2003000800010
Abstract: the study focuses on how teenage fatherhood affects the life histories of young low-income males. field work included individual interviews of young fathers living in a shantytown in rio de janeiro city. the argument is that an approach from the male standpoint affords access to other levels in a web of meanings and relations that refer back to the logic of contraception, the formation of couples, and active fatherhood. the argument also highlights the links between type of relationship and partnership, use and non-use of contraceptive methods, and the meanings of fatherhood for young low-income males. it highlights that entering actively into fatherhood helps boys consolidate their image as "mature", "responsible", "adult" men.
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