Characterization of xanthan gum produced from sugar cane broth

AbstractXanthan gum was produced by Xanthomonas campestris pv. campestris NRRL B-1459 using diluted sugar cane broth in experiments that lasted 24h. The components used were in g/L: 27.0 sucrose; 2.0 Brewer's yeast; and 0.8 NH4NO3. The mixture was fermented at 750rpm and 0.35vvm. These conditions produced xanthan gum with the desired molecular weight and total sugar content, which were 4.2×106Da and 85.3%, respectively. The sugar consisted of 43% glucose, 32% mannose and 24% glucuronic acid in a 1.79:1.33:1 ratio. The xanthan gum produced by this method was confirmed by comparing the infrared spectrum of commercial xanthan gum with the infrared spectrum of the xanthan gum produced using this method. The infrared spectra were very similar, which confirmed the identity the xanthan gum produced using our method. The xanthan gum was also evaluated using Proton Nuclear Magnetic Resonance (1H NMR)

Biosorption of lead by the brown seaweed Sargassum filipendula - batch and continuous pilot studies

The biosorption of lead by the brown alga Sargassum filipendula was studied. pH 4.0 was the optimum value for the biosorption of lead. Isotherms indicated that for solutions containing 0.03 \ub1 0.001 up to 3.27 \ub1 0.04 mmol/L of lead, 2.0g/L was the optimum biomass concentration. The Langmuir model was fitted to represent the experimental data, and the kinetics of biosorption presented equilibrium in 30 min. The continuous system operated for 56 hrs presenting a 100% binding of ionic lead, which corresponds to an accumulation of 168 g lead, equivalent to a load of 1.7 mmol ionic lead/g Sargassum filipendula. The results that were obtained in a continuous system showed a gradual saturation of the biomass in the reactors

Sintese e estudo do desempenho de suportes polimericos na imobilização de enzimas

Orientador: Edison BittencourtDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de CampinasResumo: A técnica de imoblização de enzimas vem sendo muito pesquisada atualmente, devido à possibilidade de sua utilização em processos enzimáticos que requerem alto custo na recuperação deste catalisador do meio reacional. As enzimas utilizadas nesse estudo foram a invertase e a amiloglicosidase imobilizadas nas resinas N-metilolacrilamida e uréia-formaldeído na forma pulverizada e impregnadas em microcamadas sobre malhas de poliéster. Neste trabalho foram estudadas a síntese e a caracterização das resinas, a preparação dos suportes, a caracterização das enzimas em fase líquida, e a influência de parâmetros importantes no desempenho das enzimas imobilizadas e no processo de imobilização, tais como: temperatura, pH, força iônica da solução tampão, estabilidade do catalisador após uso prolongado, agitação, concentração de enzimas nos suportes, grau de retenção das resinas nos tecidos, tempo de estocagem, estabilidade térmica e a conversão em função do tempo de reação. Foi desenvolvido ainda um estudo cinético das enzimas, imobilizadas em reator de leito fixo e um estudo da estabilidade operacional em reatores de leito fixo e de leito fluidizado. Os resultados experimentais conduziram à determinação de condições ótimas de operação, e mostraram um comportamento cinético segundo a equação de Michaelis-Menten, para ambas as enzimas em fase líquida e imobilizadas. O reator de leito. fixo comportou-se, aproximadamente, como um reator tubular ideal. A estabilidade operacional mostrou um tempo de meia-vida para as enzimas imobilizadas, um pouco superior aos valores obtidos em outros trabalhos. De maneira geral, apesar de se: verificar uma queda significativa na atividade catalítica das enzimas imobilizadas, relativa às enzimas livres, os resultados obtidos com esses suportes mostraram-se superiores aos encontrados por vários pesquisadores.Abstract: Enzyme immobilization is presently being investigated widely due to the possibility of its application in enzymatic processes with high cost of catalyst recuperation from the reaction medium. In this study, invertase and-amiloglicosidase were immobilized in N-metilolacrylamide and urea-formaldehyde resins impregnated in microlayers on polyester lattice, and polymerized resins pulverized by ball milling. Items studied were synthesis, resin characterization, lattice preparation, enzyme characterization in the liquid phase, and the influence of parameters important to immobilized performance and the immobilization process, such as temperature, pH, ionic force of the buffer solution, catalyst stability after prolonged use, agitation, enzyme concentration, level of retention of enzyme, storage time, thermal stability and conversion as function of reaction time. Also studied were kinetics of immobilized enzymes in a fixed bed reactor and operational stability in fixed and fluidized beds reactors. Optimum operating conditions were determined Kinetic behavior of both enzymes in the liquid and immobilized phases was according to the Michaelis-Menten equation. The fixed bed reactor performed approximately like an ideal tubular reactor. The half life of immobilized enzymes was found be slightly superior to that obtained by other workers. In general, catalytic activity of immobilized enzymes is significantly lower than that free enzymes. Results obtained superior to those obtained by other workers.MestradoMestre em Engenharia Químic

Improvement of glycerin removal from crude biodiesel through the application of a sulfonated polymeric adsorbent material

The proposal of suitable processes for glycerin removal from crude biodiesel is an important task for making the overall biodiesel production process environmentally friendly and economically viable. In this article, we propose a dry purification process for biodiesel treatment with different polymeric materials [chitosan, cellulose acetate, poly(vinyl alcohol) (PVA), and sulfonated PVA]. Except for pure PVA, all of the proposed materials were able to reduce the free glycerin content of crude biodiesel from 0.03 wt % to values lower than 0.02 wt %. When the PVA was sulfonated, the glycerin removal increased from 12 to 82% compared that of pure PVA. The glycerin content in the biodiesel sample treated with sulfonated PVA was 0.0055 wt %. Mid-IR spectrometric analysis showed that the sulfonation of PVA increased the band due to H-O-H stretching vibrations; this enabled greater hydrogen bonding between glycerol and the -SO3- groups of the sulfonated adsorbent13438CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPES

Stabilization of açaí (Euterpe oleracea Mart.) juice by the microfiltration process

Açaí berry, a Brazilian palm fruit widely distributed in northern South America, is acknowledged for its functional properties such as high antioxidant capacity and anti-inflammatory activities. Although the açaí juice is highly appreciated in Brazil and even worldwide, its commercialization is still limited. Microfiltration process is largely applied in juice processing, eliminating many of the traditional processing steps and reducing time, energy and addition of clarifying agents. Furthermore, microfiltration process may eliminate microorganisms and compounds responsible for turbidity in the juice. Current assay applies a microfiltration process to obtain a stabilized açaí permeate pulp. Microfiltrations of açaí pulp were carried out in a dead end configuration with a flat membrane of 0.22 μm pore size. Permeate pulp was characterized according to its turbidity, lipid concentration and microbiological analysis. Initial permeate flux was 103 kg m-2 h-1. After an initial flux decline during 30 min., due to membrane compaction and fouling occurrences, flux was stabilized at 20 kg m-2 h-1. The microfiltration process reduced the initial açaí pulp turbidity by 99.98% and lipids were not identified in the permeate. Microbiological analysis showed that the contamination by microorganism decreased in the permeate pulp when compared to that in raw açaí pulp.Açaí berry, a Brazilian palm fruit widely distributed in northern South America, is acknowledged for its functional properties such as high antioxidant capacity and anti-inflammatory activities. Although the açaí juice is highly appreciated in Brazil and even worldwide, its commercialization is still limited. Microfiltration process is largely applied in juice processing, eliminating many of the traditional processing steps and reducing time, energy and addition of clarifying agents. Furthermore, microfiltration process may eliminate microorganisms and compounds responsible for turbidity in the juice. Current assay applies a microfiltration process to obtain a stabilized açaí permeate pulp. Microfiltrations of açaí pulp were carried out in a dead end configuration with a flat membrane of 0.22 μm pore size. Permeate pulp was characterized according to its turbidity, lipid concentration and microbiological analysis. Initial permeate flux was 103 kg m-2 h-1. After an initial flux decline during 30 min., due to membrane compaction and fouling occurrences, flux was stabilized at 20 kg m-2 h-1. The microfiltration process reduced the initial açaí pulp turbidity by 99.98% and lipids were not identified in the permeate. Microbiological analysis showed that the contamination by microorganism decreased in the permeate pulp when compared to that in raw açaí pulp.

Clarification of passion fruit juice with chitosan: Effects of coagulation process variables and comparison with centrifugation and enzymatic treatments

AbstractClarification is an important step in the fruit juice processing industry. In this study, chitosan from shrimp shells is proposed as an alternative aid for passion fruit juice clarification being a natural and environmental friendly adsorbent. Experiments were carried out in Jar tests varying chitosan concentration, pH, and slow velocity speed and time. The obtained results were evaluated in terms of turbidity, color, total soluble solids (TSSs), and viscosity reductions. The best condition found in these tests for chitosan treatment was compared with centrifugation and enzymatic treatments. Two different rotation speeds (4000 and 12,000rpm) were applied for the centrifugation process. Enzymatic treatment was carried out with 1mLL−1 of Pectinex 3X L (Novo Nordisk, Switzerland) for 90min, at 50°C. The enzymatic treatment was reliable only for viscosity reduction, while the chitosan treatment after a mild centrifugation showed the best result for passion fruit clarification