38 research outputs found

    Aflatoxins

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    Aflatoxins are a group of highly toxic and carcinogenic substances that occur naturally and can be found in food substances. Aflatoxins are secondary metabolites of certain strains of fungi Aspergillus flavus and Aspergillus parasiticus as well as the less common Aspergillus nomius. Aflatoxins B1, B2, G1, and G2 are the most important members, which can be categorized into two groups according to chemical structure. As a result of the adverse health effects of mycotoxins, their levels have been strictly regulated, especially in food and feed samples. Therefore, their accurate identification and determination remain a herculean task due to their presence in the complex food matrix. The great public concern and the strict legislation incited the development of sensitive analytical methods that are discussed in this book

    Phytochemical Omics in Medicinal Plants

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    Medicinal plants are used to treat diseases and provide health benefits, and their applications are increasing around the world. A huge array of phytochemicals have been identified from medicinal plants, belonging to carotenoids, flavonoids, lignans, and phenolic acids, and so on, with a wide range of biological activities. In order to explore our knowledge of phytochemicals with the assistance of modern molecular tools and high-throughput technologies, this book collects recent innovative original research and review articles on subtopics of mechanistic insights into bioactivities, treatment of diseases, profiling, extraction and identification, and biotechnology

    Fungi and Fungal Metabolites for the Improvement of Human and Animal Nutrition and Health

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    The purpose of this book was not to provide a comprehensive overview of the vast arena of how fungi and fungal metabolites are able to improve human and animal nutrition and health; rather, we, as Guest Editors, wished to encourage authors working in this field to publish their most recent work in this rapidly growing journal in order for the large readership to appreciate the full potential of wonderful and beneficial fungi. Thus, this Special Issue welcomed scientific contributions on applications of fungi and fungal metabolites, such as bioactive fatty acids, pigments, polysaccharides, alkaloids, terpenoids, etc., with great potential in human and animal nutrition and health

    Synthesis of new pyrazolium based tunable aryl alkyl ionic liquids and their use in removal of methylene blue from aqueous solution

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    In this study, two new pyrazolium based tunable aryl alkyl ionic liquids, 2-ethyl-1-(4-methylphenyl)-3,5- dimethylpyrazolium tetrafluoroborate (3a) and 1-(4-methylphenyl)-2-pentyl-3,5-dimethylpyrazolium tetrafluoroborate (3b), were synthesized via three-step reaction and characterized. The removal of methylene blue (MB) from aqueous solution has been investigated using the synthesized salts as an extractant and methylene chloride as a solvent. The obtained results show that MB was extracted from aqueous solution with high extraction efficiency up to 87 % at room temperature at the natural pH of MB solution. The influence of the alkyl chain length on the properties of the salts and their extraction efficiency of MB was investigated

    Ultrafiltração da surfactina e manosileritritol lipídeos produzidos com manipueira como substrato

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    Orientadores: Glaucia Maria Pastore, Francisco F√°bio Cavalcante BarrosTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: A implanta√ß√£o de processos biotecnol√≥gicos incluindo a produ√ß√£o de enzimas, pept√≠deos, bioaromas, biossurfactantes, entre outros, tem aumentado de forma relevante. De modo geral, o processo de purifica√ß√£o representa ? 60% do custo de produ√ß√£o de biossurfactantes, enquanto o meio de cultura ? 30%. Este estudo descreve, pela primeira vez, a ultrafiltra√ß√£o de dois biossurfactantes (estudos independentes) que foram produzidos com res√≠duo agroindustrial como meio de cultura, ou seja, surfactina por Bacillus subtilis LB5a e manosileritritol lip√≠deos por Pseudozyma tsukubaensis, ambos usando manipueira como meio de cultura. A surfactina foi produzida por Bacillus subtilis LB5a em bioreator (3 litros de volume de trabalho). A espuma (alto teor de surfactina) foi coletada pelo topo do bioreator e utilizada para os c√°lculos de rendimento do processo e avalia√ß√£o da purifica√ß√£o por ultrafiltra√ß√£o. Foram produzidos ? 336,66 mg de surfactina por litro de meio de cultura. A ultrafiltra√ß√£o da surfactina foi realizada em duas etapas nas quais (i) as micelas de surfactinas foram retidas e, (ii) a adi√ß√£o de solvente org√Ęnico (etanol) provocou a desestabiliza√ß√£o das micelas de surfactina, permitindo que as mol√©culas de surfactina livres (n√£o agregadas) fossem recuperadas no permeado. O processo de ultrafiltra√ß√£o utilizou membranas de polietersulf√īnica com dois pontos de corte molar, 100 kDa e 50 kDa. Sendo a melhor estrat√©gia √† utiliza√ß√£o da membrana de 100 kDa na primeira etapa de ultrafiltra√ß√£o e 50 kDa na segunda etapa de ultrafiltra√ß√£o. A ultrafiltra√ß√£o do biossurfactante bruto foi associada com incrusta√ß√£o e/ou polariza√ß√£o por concentra√ß√£o. No entanto, a ultrafiltra√ß√£o do biossurfactante semipurificado resultou em alta recupera√ß√£o da surfactina (78,25%) com elevada separa√ß√£o das prote√≠nas e redu√ß√£o dos efeitos de incrusta√ß√£o e polariza√ß√£o por concentra√ß√£o. Assim, por um lado o uso de manipueira para a produ√ß√£o de surfactina reduz o custo de produ√ß√£o. Por outro lado, dificulta o processo de purifica√ß√£o. Visto que as etapas de produ√ß√£o, purifica√ß√£o e aplica√ß√£o devem ser avaliadas sequencialmente, o uso da manipueira como meio de cultura deve ser integrado a um tratamento para a retirada das prote√≠nas da manipueira antes do processo fermentativo, ou anteriormente as etapas de ultrafiltra√ß√£o (teor de prote√≠nas reduzido), como por exemplo a precipita√ß√£o √°cida e extra√ß√£o por solvente org√Ęnico, ou ainda por processos de purifica√ß√£o alternativos a ultrafiltra√ß√£o, como por exemplo a coluna de bolhas. A identifica√ß√£o estrutural qu√≠mica da surfactina foi realizada por duas an√°lises, (i) ioniza√ß√£o por dessor√ß√£o a laser assistida por matriz seguida pela detec√ß√£o em um analisador do tipo tempo de v√īo e, (ii) espectroscopia de ress√īnancia nuclear magn√©tica. Atr√°ves destas t√©cnicas foram identificadas 11 isoformas potenciais de surfactina, que por sua vez foram compostas por duas sequ√™ncias de amino√°cidos (Glu1-Leu2-Leu3-Val4-Asp5-Leu6-Leu7) e (Glu1'-Leu2'-Leu3'-Val4'-Asp5'-Leu6'-Val7'). Os manosileritritol lip√≠deos foram produzidos por Pseudozyma tsukubaensis em bioreator (3 litros de volume de trabalho) usando manipueira como meio de cultura. A espuma (alto teor de manosileritritol lip√≠deos) foi coletada pelo topo do bioreator e utilizada para os c√°lculos de rendimento do processo e avalia√ß√£o da purifica√ß√£o por ultrafiltra√ß√£o. Foram produzidos ? 1,26 g de manosileritritol lip√≠deos por litro de meio de cultura, mostrando que a manipueira √© um meio de cultura adequado a produ√ß√£o de manosileritritol lip√≠deos por Pseudozyma tsukubaensis. Os experimentos de ultrafiltra√ß√£o com os manosileritritol lip√≠deos, removeram ? 95% de prote√≠nas e retiveram (ves√≠culas) ? 80% dos manosileritritol lip√≠deos. Portanto, uma √ļnica etapa de ultrafiltra√ß√£o foi necess√°ria para a purifica√ß√£o dos manosileritritol lip√≠deos. O processo de ultrafiltra√ß√£o foi escalonado de 20 mL (dispositivo de centrifuga√ß√£o) para 500 mL (equipamento de ultrafiltra√ß√£o de bancada), e os resultados n√£o mostraram disparidade. A produ√ß√£o de manosileritritol lip√≠deos-B pela linhagem de Pseudozyma tsukunbaensis foi confirmada por cromatografia gasosa acoplada √† espectrometria de massa, ioniza√ß√£o por dessor√ß√£o a laser assistida por matriz seguida pela detec√ß√£o em um analisador do tipo tempo de v√īo e espectroscopia de ress√īnancia nuclear magn√©tica, sendo tamb√©m identificado um segundo estereois√īmeros (? 9%) relacionado ao eritritol. A recupera√ß√£o de manosileritritol lip√≠deos-B pela forma√ß√£o e arraste de espuma no bioreator integrada √† ultrafiltra√ß√£o √© uma not√°vel alternativa de purifica√ß√£o, ao inv√©s da convencional extra√ß√£o com acetato de etila seguido da purifica√ß√£o em coluna de s√≠lica. Ap√≥s estabelecer a produ√ß√£o e purifica√ß√£o de biossurfactantes, esses compostos foram avaliados quanto ao seu potencial para a recupera√ß√£o avan√ßada de petr√≥leo. Os experimentos foram realizados com 3 tipos de petr√≥leo, leve, m√©dio e pesado. Baseado nos resultados obtidos nos testes de deslocamento de √≥leo e √≠ndice de emuls√£o, manosileritritol lip√≠deos-B s√£o mais eficientes para o processo de recupera√ß√£o avan√ßada de petr√≥leo do que a surfactina, em particular para o petr√≥leo pesadoAbstract: The set of biotechnological processes including the production of enzymes, peptides, bioflavours, biosurfactants, among other, is significantly increasing. In general, the purification process represents ? 60% of production cost of biosurfactants, whereas the culture medium ? 30%. This study describes, for the first time, the ultrafiltration of two biosurfactants (independent studies), which were produced using an industrial waste as culture medium, that is, surfactin by Bacillus subtilis LB5a and mannosylerythritol lipids by Pseudozyma tsukubaensis. Surfactin was produced by Bacillus subtilis LB5a at top-bench bioreactor scale (3 liters of working volume). The foam (high concentration of surfactin) was collected by the top of bioreactor and used for the calculations of yield of process and evaluation of purification by ultrafiltration. The yield was ? 366.66 mg of surfactin by liter of culture medium. The ultrafiltration of surfactin was carried out in two-steps (i) the micelles were retained and, (ii) the adition of organic solvent (ethanol) destabilized the surfactin micelles, allowing the free surfactin (unaggregated) be recovered in the permeate. For the process of ultrafiltration, polyethersulfone membranes with two molecular weight cut-off, 100 kDa and 50 kDa, were used. The best strategy was the use of membrane of 100 kDa in the first step of ultrafiltration and 50 kDa in the second step of ultrafiltration. The ultrafiltration of crude biosurfactant was associated with fouling and/or concentration polarization. However, the ultrafiltration of semi-purified biosurfactant resulted in high recovery of surfactin (78.25%), high sepration from proteins and reduced effects of fouling and/or concentration polarization. Thus, on one hand the use of cassava wastewater for the production of surfactin decreases the production costs. On the other hand, makes harder the purification process. Since the steps of production, purification and application should be evaluated sequentially, the use of cassava wastewater has to be integrated to a treatment for remove the proteins before the fermentation process, or before the ultrafiltration steps (lower concentration of proteins), for instance acid precipitation and extraction by organic solvent, or even alternative process of purification, for instance bubble column. The chemical structure identification of surfactin was carried out by two analyses: (i) matrix assisted lazer desorption ionization followed by the detection using analyzer of time of flight and, (ii) nuclear magnetic resonance spectroscopy. By the analyses of these two techniques were identified 11 potential isoforms of surfactin, in which are composed by two sequences of amino acids (Glu1-Leu2-Leu3-Val4-Asp5-Leu6-Leu7) and (Glu1'-Leu2'-Leu3'-Val4'-Asp5'-Leu6'-Val7'). Mannosylerythritol lipids were produced by Pseudozyma tsukubaensis at top-bench bioreactor scale (3 liters of working volume) using cassava wastewater as culture medium. The foam (high concentration of mannosylerythritol lipids) was collected by the top of bioreactor and used for the calculations of yield of process and evaluation of purification by ultrafiltration. The yield was ? 1.23 g of mannosylerythritol lipids by liter of culture medium, which demonstrates that cassava wastewater is a good culture medium for the production of mannosylerythritol lipids by Pseudozyma tsukubaensis. The experiments of ultrafiltration with mannosylerythritol lipids removed ? 95% of proteins and retained (vesicles) ? 80% of mannosylerythritol lipids. Therefore, only one step of ultrafiltration was needed for the purification of mannosylerythritol lipids. The process of ultrafiltration was scaled-up from 20 mL (ultrafiltration device) to 500 mL (top-bench ultrafiltration equipment), and the results were similar. The production of mannosylerythritol lipids-B by Pseudozyma tsukunbaensis was confirmed by gas chromatography coupled to mass spectrometry, matrix assisted lazer desorption ionization followed by the detection using analyzer of time of flight and nuclear magnetic resonance spectroscopy. It was also identified a second stereoisomer (? 9%) related to erythritol. The recovery of mannosylerythritol lipids-B by the foam overflow on the top of bioreactor integrated to ultrafiltration is a remarkable alternative of purification, instead of the traditional extraction using ethyl acetate followed of silica column. After the production and purification of biosurfactants, their potentials for enhanced oil recovery were evaluated. The experiments were carried out with 3 sorts of oils, light, medium and heavy. According to the results obtained of oil displacement and emulsification index tests, mannosylerythritol lipids-B are more efficient on microbial enhanced oil recovery, em particular for heavy oilDoutoradoCi√™ncia de AlimentosDoutor em Ci√™ncia de Alimentos2011/22776-5, 2012/20982-0FAPES

    Promising Detoxification Strategies to Mitigate Mycotoxins in Food and Feed

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    This book is a printed edition of the Special Issue Promising Detoxification Strategies to Mitigate Mycotoxins in Food and Feed that was published in Toxin

    Laccase production by selected bacteria species isolated from some aquatic and terrestrial milieu of the Eastern Cape : applications in wastewater treatment

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    Aromatic pollutants are a diverse group of chemicals which are continuously produced from industrialization, urbanization and sophistication in technological advancement. Pristine water source polluted by these chemicls makes the water unsafe for human consumption, and as well disrupts the trophic structure of the aquatic milieu. Physico-chemical treatment techniques employed so far have been accompanied by major drawbacks which have overriden the relative successes recorded, hence, greener, simpler and more efficient methods of pollutant transformation is imperative. The prospect of enzymatic treatment of pollutants has gradually been receiving growing attention in contemporary times due to the their environmental friendliness and production economic feasiblity. Laccase, a multicopper oxidase has heightened its appeal towards environmental and biotechnological applications due to its broad substrate specificity and its requirement of atmospheric molecular oxygen as a cosubstrate and the discharge of water as the byproduct. Hence, this present study was designed to evaluate the biotechnological potentials of laccases produced by some bacteria species from some aquatic biomes of the Eastern Cape Province, South Africa. The laccase-producing bacteria were isolated from selected environmental samples by selective enrichment using selective aromatic compounds as sole carbon source and subsequently, laccase-screening phenolic substrates. The laccase-producing bacteria were identified by molecular techniques as proteobacteria belonging to the following genera: Achromobacter, Bordetella, Citrobacter, Pseudomonas and Stenotrophomonas. Optimisation of laccase production in a submerged fermentation was by traditional and statistical methods, where four isolates (Hb9c; Achromobacter xylosoxidans HWN16, Hb16c; Bordetella bronchisepta HSO16, Berl11b2; Stenotrophomonas maltophilia BIJ16, Ie1c; Citrobacter freundii LLJ16) were evaluated for the fermentative production of laccase from lignocellulosic agroindustrial residues. Predictions from statistical optimisation showed that weakly acidic conditions (pH 5) and low agitation speed (100 rpm) were required for maximum laccase production from mandarin peelings (0.5 g/200 mL) and NaNO3 (0.25 g/200 mL) in Hb9c, maize stover (0.50 g/200 mL) and NaNO3 (0.050 g/200mL) in Berl11b2 while a lower agitation speed (50 rpm) was required for maximum laccase output from 2.0 g/200 mL maize stover and 0.050 g/200 mL KNO3 in Ie1c. However, 2.50 g/200 mL wheat bran, 0.050 g/200 mL yeast extract and 50 rpm agitiation under acidic conditions (pH3) yielded maximum laccase titres in Hb16c. Further characterisation of Hb9c and Ie1c laccase secretions portrayed their polyextremotolerant capacities. They were active at a broad range of tempertaure (0-90 degreesC); with optima at 70¬įC (Hb9c) and 60¬įC (Ie1c), pH (3-11); with optima at pH 6 (Ie1c) and pH 8 (Hb9c), respectively, and were equally thermo- and pH-stable. Their activities were either improved or left unabated by high concentrations of cations, detergents, and chloride. In addition, catalytic activities of Hb9c and Ie1c laccase secretions increased when they were preincubated with 2 ‚Äď 20 percent of fluoride, a potent inhibitor. Consequently, a molecular perspective depicted the isolates to have multiple homologous laccase encoding genes. The enzymes were successfully immobilised on solid supports comprising gelatin and Na-alginate with a recovery of cca. 85 percent residual activity after 8 cycles of oprertional stability experiments. The immobilised laccases were remarkable in the decolourisation of synthetic dyes, albeit, free forms also elicited satisfactory performances. Ultimately, the application of free laccases in denim bleaching, individually or with a blend of a mediator, ABTS, showed that denim colours could be bleached without the need for chemical bleaching agents. The results obtained suggest the bacteria laccases produced from lignocellulosic wastes may serve as potent degraders of phenolic pollutants in water and, may also contribute to the bioeconomy and promote greener techniques for industrial applications
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