54 research outputs found

    Composição mineral de vinhos orgânicos Sauvignon blanc elaborados a partir de diferentes fases de maturação das uvas no Vale do São Francisco, Brasil.

    Get PDF
    O objetivo do presente trabalho foi avaliar os minerais presentes em vinhos elaborados a partir de uvas produzidas de cultivo orgânico, da cultivar Sauvignon Blanc, colhidas em diferentes fases de maturação

    Composição mineral de vinhos orgânicos Sauvignon blanc elaborados a partir de diferentes fases de maturação das uvas no Vale do São Francisco, Brasil.

    Get PDF
    O objetivo do presente trabalho foi avaliar os minerais presentes em vinhos elaborados a partir de uvas produzidas de cultivo orgânico, da cultivar Sauvignon Blanc, colhidas em diferentes fases de maturação

    Ethanol production from xylose by pichia stipitis NRRL Y-7124 in a stirred tank bioreactor

    Get PDF
    The ethanol production by Pichia stipitis was evaluated in a stirred tank bioreactor using semidefined medium containing xylose (90.0 g/l) as the main carbon source. Experimental assays were performed according to a 22 full factorial design to evaluate the influence of aeration (0.25 to 0.75 vvm) and agitation (150 to 250 rpm) conditions on ethanol production. In the studied range of values, the agitation increase and aeration decrease favored ethanol production, which was maximum (26.7 g/l) using 250 rpm and 0.25 vvm, conditions that gave a volumetric oxygen transfer coefficient (kLa value) of 4.9 h-1. Under these conditions, the ethanol yield factor, ethanol productivity, and the process efficiency were 0.32 g/g, 0.32 g/l.h, and 63%, respectively. These results are promising and contribute to the development of a suitable process for ethanol production from xylose by Pichia stipitis.The authors gratefully acknowledge Santander, Fapesp, Capes, and CNPq (Brazil)

    RELATIONSHIP BETWEEN MORPHOLOGY, RHEOLOGY AND GLUCOAMYLASE PRODUCTION BY Aspergillus awamori IN SUBMERGED CULTURES

    No full text
    The influence of inoculum preparation on Aspergillus awamori morphology, broth rheology and glucoamylase synthesis in submerged cultures was investigated. A series of runs were performed in fermenters, using initial total reducing sugar concentrations of 20 g/L and 80 g/L. The inocula were prepared in a rotary shaker, at 35oC and 200 rev/min, using a spore concentration of 9.2 x 105 spores/mL and varying both cultivation time and medium pH during the spore germination step. Three types of inocula were used: inoculum cultivated for 24 hours at an initial pH of 5.0, and inocula cultivated for 7 hours at both a pH of 2.5 and a pH of 5.5. Regarding glucoamylase production, the inoculum which provided the best results was shaker cultivated for 7 hours at a pH of 2.5. This inoculum produced glucoamylase of about 1,221 U/L in the fermenter, which was between 20% and 30% higher than those obtained using other inocula

    Residual fractions from Arthrospira platensis

    No full text

    Avaliação de um reator de lodo ativado aplicado à nitrificação utilizando ensaios cinéticos = Evaluation of an activated sludge reactor applied to nitrification using kinetic assays

    No full text
    Neste trabalho, um reator em escala laboratorial de lodo ativado, aplicado ao processo da nitrificação, foi acompanhado por meio de ensaios cinéticos de atividade específica. A atividade de nitrificação da biomassa foi determinada por respirometria nacaracterização do inóculo e na avaliação da biomassa do reator em duas condições: durante a alimentação do reator com meio sintético autotrófico; e após a sua alimentação com efluente de um reator UASB, utilizado para desnitrificação. O reator atingiu uma eficiência em torno de 90% de nitrificação em ambas as condições de operação. O modelo cinético de Andrews, que inclui uma constante da inibição pelo substrato (Ki), ajustou-se melhor aos resultados obtidos nos testes de atividade do que o de Monod. Entretanto, observou-se aumento daconstante de inibição (Ki) do lodo após operação do reator em relação ao inóculo, demonstrando a adaptação da biomassa às novas condições (cargas) de nitrificação.<br><br>In this work, an activated sludge lab-scale reactor used fornitrification was monitored by specific activity kinetic assays. The nitrification biomass activity was carried out by respirometric methods in order to characterize the inoculum and the reactor sludge after two different operation conditions: during the feeding of the reactor with synthetic autotrophic medium, and after feeding it with effluent from an UASB reactor used for denitrification. The efficiency of nitrification reached 90% in both operation conditions. Results obtained by the kinetic activity assays were better adjusted by the kinetic model of Andrews, which includes the inhibition constant by the substrate (Ki), than the Monod model. However, an increase was observed in the inhibition constant (Ki) of the sludge after the operation of the reactor as compared with the inoculum. This effect demonstrates an adaptation of the biomass to the new nitrification conditions (loading rate)

    CONSTRUCTION AND OPERATION OF AN IMPELLER RHEOMETER FOR ON-LINE RHEOLOGICAL CHARACTERIZATION OF NON-NEWTONIAN FERMENTATION BROTHS

    No full text
    The present work describes the development and operation of a continuous rotational impeller rheometer for on-line rheological measurements in fermentation broths. In an initial step three devices were calibrated, two of them utilizing helical ribbon impellers and the third a six-bladed impeller. The calibration constants obtained were within the range mentioned in the literature, showing consistency with the methodology employed. In the sequence, the system with one of the helical ribbon impellers (HR39) was selected for on-line continuous rheological measurements due to its small dimensions and its wide measurement range. Finally, the performance of the proposed device, in terms of rheological measurements in Aspergillus awamori broths, was compared to that of a commercial bench rheometer. The comparison of on-line and off-line rheological measurements showed a good agreement between both measurement techniques. Furthermore, results suggest that the proposed on-line rheometer features higher sensitivity and easier operation than the commercial rheomete
    corecore