Extração e purificação de clorofila a, da alga Spirulina maxima: um experimento para os cursos de química

This work describes a simple and economical experiment for the extraction and purification of chlorophyll a from Spirulina maxima. Extraction and purification of natural compounds can be considered one of the most illustrative experiments that can be performed in Organic Chemistry courses. Particularly, the chromatography of dyes and pigments allows students to have a better comprehension of the chromatography separations. These compounds represent an important class of organic pigments applied in pharmaceutical, cosmetic, detergent compositions, and various other fields and can be extracted from plants and algae. To extract, separate and purify chlorophyll a from associated pigments such as xanthophylls, carotenes, and pheophytins, very costly processes are reported. The present approach is perfectly adequate for use in Chemistry experiments for undergraduate students.

Produção, purificação e aumento da performance de ciclodextrina glicosiltransferases para produção de ciclodextrinas

Biospecific affinity chromatography was used to purify three cyclodextrin glycosyl transferases (CGTases) obtained from microorganisms isolated of soil. The cyclodextrins (CDs) production by CGTases was evaluated using starches from different sources. CDs were measured through the Complexation Theory and by HPLC. CGTase from Bacillus firmus strain 7B showed the best production (30 mmol/L of β-CD and 4.3 mmol/L of γ-CD), and its cultivation conditions were optimized. The maximum enzymatic activity was achieved using lung peptone, soluble starch and agitation speed of 160 rpm. Studied CGTases were shown quite interesting for the industrial production of CDs.

Utilização de diferentes tipos de policloretos de alumínio para purificação de hidrolisado de bagaço de cana através da técnica de coagulação e floculação

In order to investigate the action of the flocculating agents Panfloc and Panclar a full factorial design 2³ and a Central Composite design 2² were carried out. The control variables were the flocculant concentration, pH and temperature. The response variables were phenolic compounds reduction and spectral area reduction. The best conditions of treatment was hydrolyzate at pH 9 for both coagulants, but the use of Panfloc was more effective in the phenolic compounds reduction (73.9%) and spectral area reduction (65.8%).

Purificação e caracterização da quitinase de uva (Vitis vinífera L. cv Red Globe) para a produção de quitosana a partir de quitina de camarão

Chitinase is produced by a wide variety of plants as a defense against peste attacks. In this study, grape chitinases were purified 16 times by fractionation in 80% ammonium sulfate followed by dialysis and filtration. Purified chitinases exhibited enzymatic activity toward chitin azure. The yield of purified chitinase was 229 mg/L with chitinase activity of 563 U/g. Chitinases had molecular masses of 24 and 30 kDa, as evaluated by SDS-PAGE 12.5%. Two pH optima were determined 3.0 and 6.0. The optimal temperature was 42 °C. Pre hydrolysis of crystalline shrimp chitin by chitinases caused in an increase in the deacetylation ratio triggered by chitin deacetylase producing chitooligosaccharides with DA (degree acetylation) of 58.8%.

Filmes ultrafinos de ésteres de celulose: preparo, caracterização e imobilização de proteínas

In this study cellulose acetate butyrate (CAB) and carboxymehtylcellulose acetate butyrate (CMCAB) films adsorbed onto silicon wafers were characterized by means of ellipsometry, atomic force microscopy (AFM), sum frequency generation spectroscopy (SFG) and contact angle measurements. The adsorption behavior of lysozyme (LIS) or bovine serum albumin (BSA) onto CAB and CMCAB films was investigated. The amounts of adsorbed LIS or BSA onto CMCAB films were more pronounced than those onto CAB films due to the presence of carboxymethyl group in the CMCAB structure. Besides, the adsorption of BSA molecules on CMCAB films was more favored than that of LIS molecules. Antimicrobial effect of LIS bound to CAB or CMCAB layers was evaluated using Micrococcus luteus as substrate.

Utilização de argilas para purificação de biodiesel

This work describes the results of the purification of methyl biodiesel, obtained by oxidized soybean oil, using different methods. After the ester separation from the glycerin by decanting, the ester was purified each time with distillation, washing with water and adsorption with bauxite, bentonite and attapulgite. The removal of total contamination, unsaponifiable material, concentrations of free glycerin and soap were analyzed in the purified ester phase. The best result of purification was observed with the use of bentonite and bauxite, in the removal of soap and free glycerin respectively.

Fracionamento de cobre em proteínas do plasma, músculo e fígado de tilápia do Nilo

Copper fractionation in plasma, muscle and liver of Nile tilapia was performed after protein separation by 2D-PAGE. SR XRF analysis indicated the presence of copper in three protein spots of plasma, and in two protein spots of muscle and liver, respectively. Copper ions were found to be distributed mostly in proteins that had a molar mass of less than 54 kDa and greater than 13 kDa and a pI in the 5.3-9.3 range. The copper concentration bound to these proteins was determined by GFAAS which showed concentrations in the 1.20-4.82 mg g-1 range.

Otimização e validação da extração sólido-líquido e purificação em baixa temperatura de HPAs em lodo de esgoto

In this study, a method of solid-liquid extraction and purification at low temperature (SLE-PLT) to determine 16 polycyclic aromatic hydrocarbons (PAHs) in sewage sludge was optimized and validated. The analyses were performed by HPLC-UV. The extraction phase, homogenization procedure, influence of pH, ionic strength and clean-up of the extracts were optimized. Recoveries were higher than 63.4% for 11 PAHs. The correlation coefficients were greater than 0.99 and limits of detection and quantitation were less than 0.060 and 0.15 µg g-1, respectively. These values were lower than the maximum residue limits of PAHs established by European legislation. SLE-PLT proved a more practical, economical method with fewer steps compared to Soxhlet extraction (reference method) for PAHs in sewage sludge.

Determinação da atividade antitríptica em proteínas de produtos do amendoim isoladas por cromatografia de afinidade

The peanut is an oleaginous plant of high nutritional value, a source of protein and a trypsin inhibitor. Trypsin inhibitors are proteins present in the vegetable kingdom, considered anti-nutritional factors for animals. However, there have been several recent reports about their heterologous and beneficial effects on human health. These important effects have been the focus of studies investigating these inhibitors in foods. The aim of the present study was to isolate and determine the estimated molecular mass and specific inhibitory activity, for trypsin in the Japanese peanut, peanut butter, and peanut nougat using the techniques of precipitation with ammonium sulfate and affinity chromatography on trypsin - Sepharose CNBr 4B. The techniques used in this study were efficient for isolating the protein inhibitors with antitryptic specific activity of 694 UI mg-1, 823 UI mg-1 and 108 UI mg-1 for the Japanese peanut, peanut nougat, and peanut butter, respectively. The techniques featured high selectivity of the adsorbent, with consequent efficiency in isolation, given the low amount of dosed proteins and specific antitryptic activity presented by the products studied. The various health-related benefits show the importance of detecting and isolating efficient trypsin inhibitors in foods, taking into account the health claims attributed to the vegetable and its high consumption by humans.

DISTRIBUIÇÃO, ATIVIDADE BIOLÓGICA, SÍNTESE E MÉTODOS DE PURIFICAÇÃO DE PODOFILOTOXINA E SEUS DERIVADOS

Podophyllotoxin is the most studied lignan because of its use as an antimitotic agent and because it is a precursor of pharmacologically active derivatives. This review describes the anticancer activities of podophyllotoxin and the different processes that have been developed for its extraction and purification from Podophyllum spp. In addition, the synthesis routes of this compound and the development of three semi-synthetic procedures to obtain etoposide, teniposide, and Etopophos are detailed.

PARTIÇÃO DE PROTEÍNAS DE SORO DE LEITE EM SISTEMAS AQUOSOS BIFÁSICOS BASEADOS EM LÍQUIDOS IÔNICOS

In this work, we used an aqueous two-phase system (ATPS) consisting of the ionic liquid [C4mim][Cl] and the salt K2HPO4 to partition α-lactalbumin, β-lactoglobulin, and lactoferrin whey proteins. Extraction efficiency values above 87% indicate that the proteins primarily migrated to the ionic liquid-rich phase (top phase). Partition coefficient values ranged from 6.17 to 8.93 for a-lactalbumin, from 22.80 to 34.55 for β-lactoglobulin, and from 26.46 to 40.06 for lactoferrin. Therefore, the saline ATPS with the ionic liquid examined in this study can be considered to be a promising alternative for extracting whey proteins.

Análise de proteínas e isoenzimas de isolados de Rhizoctonia spp. patogênicos a Eucalyptus

Objetivou-se caracterizar isolados de Rhizoctonia solani AG1 e AG4 e isolados binucleados de Rhizoctonia spp. patogênicos a Eucalyptus, por meio de eletroforese de proteínas, em gel de poliacrilamida, e de isoenzimas (ACP, 6-PGDH, LAP, SOD, MDH e IDH), em gel de amido. Para comparação, incluíram-se alguns isolados brasileiros de outros hospedeiros e isolados-padrões de R. solani AG1, procedentes do Japão. Observaram-se diferenças nos padrões gerais de proteínas e nos fenótipos isoenzimáticos entre isolados binucleados e multinucleados e entre isolados de diferentes grupos e subgrupos de anastomose. Isolados de R. solani AG1, procedentes do Brasil e Japão, apresentaram baixa similaridade nos padrões de proteínas e de isoenzimas. Isolados brasileiros morfologicamente semelhantes a R. solani AG1-IB (microesclerodiais) apresentaram padrões de proteínas similares e um maior número de fenótipos isoenzimáticos idênticos entre si. Esta tendência foi independente do hospedeiro e da origem geográfica. Variações nos padrões de proteínas e de isoenzimas foram também observadas dentre isolados brasileiros de R. solani AG4. Discute-se o uso da eletroforese de proteínas e isoenzimas na caracterização de isolados de Rhizoctonia spp. e em estudos genéticos e filogenéticos de fungos deste gênero.

Purificação de metabólitos fúngicos com efeitos tóxicos sobre Meloidogyne incognita

Objetivando o desenvolvimento de novas metodologias de controle de fitonematóides, este trabalho buscou purificar as substâncias nematicidas produzidas por Cunninghamella elegans, Fusarium sp., Paecilomyces lilacinus eP. variotii. Esses fungos foram cultivados em meio líquido Czapek-Dox durante 15 dias, a 25 ºC, em agitador orbital. Em seguida, filtraram-se as misturas, o que permitiu a obtenção de soluções que foram concentradas sob vácuo e submetidas à purificação direcionada por testes in vitro com Meloidogyne incognita. Observou-se que os filtrados de P. lilacinus e P. variotii perdiam suas atividades nematicidas após a concentração sob vácuo, sugerindo que as substâncias ativas produzidas por esses fungos são consideravelmente voláteis. Para o filtrado de Fusarium sp., observou-se perda total da atividade contra M. incognita após fracionamento em coluna de sílica gel, indicando instabilidade da substância nematicida frente às condições empregadas.Do filtrado de C. elegans isolou-se uma substância que, em solução aquosa na concentração de 250 ppm, imobilizou 94% dos juvenis do segundo estádio de M. incognita expostos a tal solução durante 48 h.

Extratos vegetais com propriedades nematicidas e purificação do princípio ativo do extrato de Leucaena leucocephala

Inicialmente buscou-se identificar plantas com extratos metanólicos ativos in vitro contra o nematóide Panagrellus redivivus. Das 24 espécies vegetais estudadas, constatou-se que os melhores resultados foram obtidos com Leucaena leucocephala, que causou mortalidade de 93% dos indivíduos expostos ao seu extrato por 24 h. Em seguida, submeteu-se o referido extrato a fracionamento direcionado pelos testes in vitro com P. redivivus, o que possibilitou isolar uma substância nematicida que, segundo análises preliminares, correspondia a um alcalóide.

Peroxidases ativadas por frações protéicas de extrato biológico eficaz na proteção do tomateiro contra a mancha bacteriana

Uma formulação natural (VLAF) obtida da extração aquosa a frio de pó de tecido necrótico de lobeira (Solanum lycocarpum), infectado por Crinipellis perniciosa (Stahel) Singer, promoveu redução significativa no progresso da mancha foliar bacteriana (Xanthomonas campestris pv. vesicatoria), quando previamente pulverizado em folhas de tomateiro. Duas frações obtidas por precipitação salina, F0/30 e F30/60, apresentaram a maior parte das proteínas do extrato VLAF e foram submetidas à cromatografia de troca catiônica para separação das proteínas contidas nas frações. Os picos não retidos dessa cromatografia foram então submetidos à cromatografia de troca aniônica. Todos os picos, retidos e não retidos das duas cromatografias, foram amostrados e pulverizados sobre plantas de tomate cv. Santa Cruz Kada. Respostas diferenciais de atividade de peroxidases foram obtidas 14 horas após pulverizações. As amostras que induziram os maiores aumentos na atividade de peroxidases nas plantas foram o pico retido em CM-celulose da F0/30 (F0-30CMR) e o pico retido em DEAE-celulose da F30/60 (F30-60DEAER). Os resultados deste estudo indicaram a viabilidade da purificação e da caracterização de proteínas ou carboidratos eliciadores provenientes de VLAF.