Phytase-Producing Bacteria from Extreme Regions in Indonesia

ABSTRACTIn this study, 154 isolates capable of producing extracellular phytate-degrading activity were isolated from four soil samples from volcanic areas in Central Java, Indonesia. Six strains with high phytate-degrading activity were selected for strain identification and characterization of the corresponding phytate-degrading enzyme. Blast analysis of 16S rRNA gene sequences revealed high similarities for all the six isolates to reference sequences belonging to the genusBacillus. Isolates MS5, MC6, D10 and D16 showed 99% sequence identity toB. cereus, while isolate MC8 exhibited 99% sequence identity toB. aryabhatti and D6 99% sequence identity toB. psychrotolerans. The crude extracellular phytase preparations from the isolates showed following optimal conditions for phytate dephosphorylation: pH 4.0 and 50°C (isolate D10), pH 5.0 and 60°C (isolate MC6, and isolate MS5), pH 6.0 and 50°C (isolate D16) and pH 6.0 and 60°C (isolate D6) and pH 6.0 and 40°C (isolate MC8). Zn2+ and Fe3+ strongly inhibited phytate dephosphorylation with all phytase preparations studied. In the presence of Ca2+, an increase in phytase activity of 10-15% was obtained.

Purification and characterisation of an extracellular phytase from Aspergillus niger 11T53A9

An extracellular phytase from Aspergillus niger 11T53A9 was purified about 51-fold to apparent homogeneity with a recovery of 20.3 percent referred to the phytase activity in the crude extract. Purification was achieved by ammonium sulphate precipitation, ion chromataography and gel filtration. The purified enzyme behaved as a monomeric protein with a molecular mass of about 85 kDa and exhibited maximal phytate-degrading activity at pH 5.0. Optimum temperature for the degradation of phytate was 55ºC. The kinetic parameters for the hydrolysis of sodium phytate were determined to be K M = 54 µmol l-1 and k cat = 190 sec-1 at pH 5.0 and 37ºC. The purified enzyme was rather specific for phytate dephosphorylation. It was shown that the phytase preferably dephosphorylates myo-inositol hexakisphosphate in a stereospecific way by sequential removal of phosphate groups via D-Ins(1,2,4,5,6)P5, D-Ins(1,2,5,6)P4, D-Ins(1,2,6)P3, D-Ins(1,2)P2 to finally Ins(2)P.

Current and projected applications of nanotechnology in the food sector: [review] / Aplicações atuais e futuras da nanotecnologia no setor alimentício: [revisão]

The prospects for applications of nanotechnology to the food sector have become more apparent over the last few years. Nanotechnology applications are expected to bring changes to the food sector, including improved production and processing techniques, improved food contact materials, modification of taste, texture and sensation, monitoring food quality and freshness, reduced fat content, enhanced nutrient absorption, and improved traceability and security of food products. A variety of food ingredients, additives, encapsulation systems and food contact materials is already available in some countries and the market for nanotechnology-derived food products and food contact materials is expected to grow worldwide. However, no clear information about the actual use of nanotechnology in the food industry is available and data on the benefits, improvements and risks of nanotechnology applications in the food sector as well as their economical competitiveness are still almost lacking.

Las posibilidades de aplicación de la nanotecnología al sector de alimentos se tornaron más evidentes en los últimos años. Se espera que su empleo introduzca cambios en el sector de alimentos, incluyendo aumentos de productividad; perfeccionamiento de los procesos; mejora de los materiales de contacto con alimentos; modificaciones de sabor, textura y sensación; vigilancia de la calidad y el frescor; reducción del contenido de grasa; aumento de la absorción de nutrientes y perfeccionamiento de la trazabilidad y seguridad de los productos alimenticios. Una variedad de ingredientes de alimentos, aditivos, sistemas de encapsulación y materiales de contacto con los alimentos ya están disponibles en algunos países y se espera que el mercado de productos alimenticios con origen en la nanotecnología aumente en todo el mundo. Sin embargo, no existe en el momento información sobre como la nanotecnología esta siendo usada en la industria de alimentos, ni datos sobre los beneficios, progresos y riesgos de su aplicación al sector de alimentos o de la competitividad económica de esta tecnología.

As perspectivas de aplicações da nanotecnologia ao setor alimentício se tornaram mais aparentes nos últimos anos. Espera-se que as aplicações da nanotecnologia trarão mudanças ao setor, incluindo técnicas aperfeiçoadas de produção e processamento, materiais que têm contato com o alimento melhorados, modificação de sabor, textura e sensação, monitoria da qualidade e frescor dos alimentos, reduzido teor de gordura, absorção de nutrientes aumentada, e melhor rastreabilidade e segurança dos produtos alimentícios. Uma variedade de ingredientes, aditivos, sistemas de encapsulação e materiais que entram em contato com o alimento já estão disponíveis em alguns países e espera-se que o mercado para produtos alimentícios derivados da nanotecnologia e materiais que entram em contato com os alimentos cresça mundialmente. Entretanto, não há claras informações disponíveis sobre o real uso da nanotecnologia na indústria de alimentos e dados sobre os benefícios, melhorias e riscos da aplicação da nanotecnologia na indústria de alimentos, bem como sua competitividade econômica ainda são quase ausentes.

Production of D-myo-inositol(1,2,4,5,6)pentakisphosphate using alginate-entrapped recombinant Pantoea agglomerans glucose-1-phosphatase

The glucose-1-phosphatase encoding gene (agp) of Pantoea agglomerans was sequenced and heterologously expressed in Escherichia coli. The enzyme showed very high homology to periplasmatic glucose-1-phosphatases of other members of the Enterobacteriaceae family. It was isolated from transformed Escherichia coli cells in a single step in high yields (32.3 ± 1.2 mg per litre of culture) by Ni-NT agarose affinity chromatography to >95 percent purity as calculated from specific activity determinations. The purified glucose-1-phosphatase was entrapped in alginate beads with an entrapment efficiency of >80 percent. Temperature stability was enhanced as a consequence of entrapment, whereas pH dependence of enzyme activity was not affected. Maximum catalytic activity of entrapped glucose-1-phosphatase was found at 70°C, whereas the free enzyme exhibited maximal activity at 60°C. A single pH optimum at pH 4.5 was determined for the free and the entrapped enzyme. Kinetic parameters for the hydrolysis of sodium phytate were found to be affected by entrapment. They were determined to be K M = 0.84 mmol l-1 and k cat = 8 s-1 at pH 4.5 and 37°C for the entrapped glucose-1-phosphatase and K M = 0.35 mmol l-1 and k cat = 20.5 s-1 for the free enzyme. Complete conversion of phytate into one single myo-inositol pentakisphosphate isomer, identified as D-myo-inositol(1,2,4,5,6)pentakis-phosphate, was shown to be feasible by using the enzyme-loaded alginate beads in batch operations. The entrapped enzyme showed a high operational stability by retaining almost full activity even after ten uses.

Functional properties of phytate / Propriedades funcionais do fitato

Phytate [myo-inositol (1,2,3,4,5,6) hexakisphosphate], a naturally compound formed during maturation of plant seeds and grains, is a common constituent of plant-derived foods. The major concern about the presence of phytate in thediet is its negative effect on mineral uptake. Minerals of concern in this regardin clude Zn2+, Fe2+/3+, Ca2+, Mg2+, Mn2+, and Cu2+. Especially zinc and iron deficiencies were reported as a consequence of high phytate intakes. In addition, a negative effect on the nutritional value of protein by dietary phytate is discussed. Consumption of phytate, however, seems not to have only negative effects on human health. Dietary phytate was reported to prevent kidney stone formation, protect against diabetes mellitus, caries, atherosclerosis and coronary heart disease as well as against a variety of cancers. Furthermore, individual myo-inositol phosphate esters have been proposed to be metabolicall y active. D-myo-inositol(1,2,6)trisphosphate, for example, has been studied in respect to prevention of diabetes complications and treatment of chronic inflammations as well as cardiovascular diseases and due to its antiangiogenic and antitumour effects myo-inositol(1,3,4,5,6) pentakisphosphate was suggested as a promising compound for anticancer therapeutic strategies

El fitato, (1,2,3,4,5,6) hexafosfato de mio-inositol, compuesto que se forma naturalmente durante la maduración de las semillas ygranos, es un constituyente común de los alimentos vegetales. La mayor preocupación con la presencia de fitato es su efecto negativo en la absorción de minerales, particularmente Zn2+, Fe2+/3+, Ca2+, Mg2+, Mn2+, e Cu2+.Las deficiencias de zinc y hierro, fueron relacionadas con altas ingestas de fitato. Es discutido también su efecto negativo en el valor biológico de las proteínas. Sin embargo, el consumo de fitato parece no tener solamente efectos negativos para la salud humana. Fue descripto, por ejemplo, un efecto protector del fitato contra la formación de cálculos renales, contra la diabetes mellitus, formación de caries, ateriosclerosis y enfermedades coronarias, como también contra una gran variedad de tipos de tumores malignos. Además, ha sido propuesto que, individualmente, algunos ésteres de fosfato de mio-inositol sean metabólicamente activos. Hay estudios relacionando el (1,2,6) trisfosfato de D-mio-inositol con la prevención de complicaciones de la diabetes y con el tratamiento de inflamaciones crónicas y de enfermedades cardiovasculares; el (1,3,4,5,6)pentafosfato de mio-inositol, debido a sus efectosanti-angiogénicos y anti-tumorales, fue sugerido como un compuesto promisor en las estratégias terapéuticas contra el cáncer

O fitato, (1,2,3,4,5,6) hexafosfato de mio-inositol], composto que ocorre naturalmente e é formado durante a maturação de sementes e grãos, é um constituinte comum de alimentos vegetais. A maior preocupação com a presença de fitato na dieta é seu efeito negativo na absorção de minerais, particularmente Zn2+, Fe2+/3+, Ca2+, Mg2+, Mn2+, e Cu2+. As deficiências de zinco e de ferro, em especial, foram relacionadas com altas ingestões de fitato. É discutido, também, o efeito negativo do fitato no valor biológico de proteínas. Por outro lado, o consumo de fitato parece não ter somente efeitos negativos para a saúde humana. Foi descrito, por exemplo, um efeito protetor do fitato contra a formação de cálculos renais, contra diabetes Mellitus, formação de cáries, aterosclerose e doença coronariana, bem como contra uma grande variedade de tipos de tumores malignos. Além disso, foi proposto que, individualmente, alguns ésteres de fosfato de mio-inositol sejam metabolicamente ativos. Assim, há estudos relacionando o (1,2,6) trisfosfato de D-mio-inositol com a prevenção das complicações do diabetes e com o tratamento de inflamações crônicas e de doenças cardiovasculares; o(1,3,4,5,6) pentafosfato de mio-inositol, devido a seus efeitos anti-angiogênicos e anti-tumorais, foi sugerido como um composto promissor nas estratégias terapêuticas contra o câncer

Genetic engineering and functional foods / Engenharia genética e alimentos funcionais

Functional foods are the food-industry response to the continuous ly increasing request of consumers for foods that are both attractive and healthy. The main targets of functional foods are intestinal health, immune system activity, mental performance, caries, menopause symptoms, cancer, cardiovascular disease, diabetes, osteoporosis and child skeletal development. Most of the functional foods designed so far are derived from traditional foods by adding so-called functional ingredients, by modifying the technological process during industrial food preparation or by modifying the composition of the raw material used for food production. However, gene technology is thought to be a powerful technique to improve the nutritional quality of food raw materials. The modification of product quality characteristics using gene technology depends on a well-establishe dunder standing of the pathways for biosynthesis of plant products, a rapidly expanding knowledge about the genetic control of these pathways, and an increasing availability of cloned genes for key enzymatic steps. Quality-improved crops derived from genetic engineering are expected to reach the market in the near future. Crops with an improved protein quality, with an improved nutritional quality of the plant oil, crops rich in vitamins, minerals, antioxidants or low in undesired compounds as well as crops with an altered secondary metabolite production or altered carbohydrate composition have been developed by genetic engineering. These examples give an idea of the genetic engineering potential to produce health-promoting foods

Los alimentos funcionales son la respuesta de la industria de alimentos a la creciente demanda de los consumidores por alimentos que sean al mismo tiempo atrayentes y saludables. Los principales objetivos de los alimentos funcionales son la salud intestinal, del sistema inmunológico,el desempeño mental, las caries, los síntomas dela menopausia, cáncer, enfermidades cardiovasculares, diabetes, osteoporosis y desenvolvimiento óseo en niños. La mayoría de los alimentos funcionales desarrollados hasta el momento son derivados de los alimentos tradicionales a los cuales se les adicionan los ingredientes funcionales, se les modifica el proceso tecnológico de industrialización o se les altera la composición de materias primas utilizadas en su producción. Sin embargo, se tiene por cierto que la tecnología genética es un instrumento poderoso para mejorar la calidad nutricional de las materias primas alimenticias. La modificación de las características de calidad del producto utilizando tecnología genética depende de un conocimiento asentado de las vías metabólicas de síntesis de productos vegetales, un conocimiento en rápida expansión sobre el control genético de tales vías y una creciente disponibilidad de genes clonados para la expresión de enzimas claves de algunos passos de esas vías. Se espera que cultivos con calidad mejorada originarios de ingeniería genéticalleguen al mercado en un futuro próximo.Cultivos con mejor calidad de proteínas y lípidos, con mayor concentración de vitaminas, minerales y antioxidantes, con bajos tenores decompuestos indeseables y también cultivos com metabolitos secundarios modificados o composición alterada de carbohidratos son ejemplos de logros ya alcanzados por la ingeniería genética. Los ejemplos mencionados permiten visualizar el potencial de la ingeniería genética para la producción de alimentos promotores de la salud

Os alimentos funcionais são a resposta da indústria alimentícia à sempre crescente demanda dos consumidores por alimentos ao mesmo tempo atraentes e saudáveis. Os principais alvos dos alimentos funcionais são a saúde intestinal, a atividade do sistema imune, o desempenho mental, cáries, sintomas da menopausa, câncer, doenças cardiovasculares, diabetes, osteoporose e desenvolvimento ósseo de crianças. A maioria dos alimentos funcionais desenvolvidos, até o momento, são derivados de alimentos tradicionais pela adição dos ditos ingredientes funcionais, modificação dos processos tecnológicos durante o preparo industrial dos alimentos ou alteração da composição das matérias-primas usadas na produção dos alimentos. Contudo, acredita-se que a tecnologia genética seja um poderoso instrumento para melhorar a qualidade nutricional das matérias-primas alimentícias. A modificação das características de qualidade do produto usando a tecnologia genética depende de um conhecimento bem embasado sobre as rotas metabólicas de síntese de produtos vegetais, um conhecimento em rápida expansão sobre o controle genético de tais rotas metabólicas, e uma crescente disponibilidade de genes clonados para expressão de enzimas-chave de alguns passos destas rotas. Espera-se que culturas com qualidade melhorada derivadas da engenharia genética cheguem ao mercado num futuro próximo. Culturas com qualidade proteica melhorada, com melhor qualidade nutricional do óleo vegetal derivado, culturas ricas em vitaminas, minerais, antioxidantes ou com baixos teores de compostos indesejáveis, bem como culturas com produção de metabólitos secundários alterados ou composição alterada de carboidratos já foram desenvolvidas pela engenharia genética. Estes exemplos dão uma ideia do potencial da engenharia genética para produzir alimentos promotores de saúde

Evaluation of viability of Aspergillus flavus and aflatoxins degradation in irradiated samples of maize

Um dos fungos mais importantes atualmente em grãos armazenados é o Aspergillus flavus, o qual produz aflatoxinas. Este fungo pode crescer em diversos substratos e representa uma séria preocupação em saúde pública e nutrição animal. Portanto, o estudo de técnicas que possam ser aplicadas no controle das aflatoxinas é de grande importância. Assim sendo, o objetivo do presente trabalho foi estudar os efeitos da radiação gama no crescimento de Aspergillus flavus Link e na degradação das aflatoxinas B1 e B2, (AFB1 e AFB2) em umidade relativa (UR) de 97-99% e atividade de água (Aa) de 0,88-0,94. Amostras de grãos de milho foram irradiadas, utilizando-se uma fonte de Cobalto 60, emissora de raios gama, com as doses de 2; 5 e 10 kGy. A irradiação foi efetiva na redução do número de Unidades Formadoras de Colônias de A. flavus, por grama, nas amostras de milho analisadas. Adicionalmente, o teste de viabilidade fluorescente (solução de diacetato de fluoresceína e brometo de etídio) revelou diminuição no número de células viáveis com o aumento das doses de irradiação e três diferentes padrões de fluorescência. Além disso, a irradiação induziu a uma parcial redução dos níveis de AFB1 e AFB2, nas doses de 2 e 5 kGy, ao passo que uma completa degradação das aflatoxinas foi observada no ensaio empregado com 10 kGy.

Bacterial phytase: potential application, in vivo function and regulation of its synthesis

The stepwise release of phosphate from phytate, the major storage form of phosphate in plant seeds and pollen, is initiated by a class of enzymes that have been collectively called phytases. The classification is solely due to the in vitro capability of these enzymes to accept phytate as a substrate. Phytases have been studied intensively in recent years because of the great interest in such enzymes for reducing phytate content in animal feed and food for human consumption. They have a wide distribution in plants, microorganisms, and in some animal tissues. Due to several biological characteristics, such as substrate specificity, resistance to proteolysis and catalytic efficiency, bacterial phytases have considerable potential in commercial applications. In bacteria, phytase is an inducible enzyme and its expression is subjected to a complex regulation, but phytase formation is not controlled uniformly among different bacteria. It was suggested that phytase is not required for balanced growth of bacterial cells, but may be synthesised in response to a nutrient or energy limitation.

Bacterial phytase: potential application, in vivo function and regulation of its synthesis

The stepwise release of phosphate from phytate, the major storage form of phosphate in plant seeds and pollen, is initiated by a class of enzymes that have been collectively called phytases. The classification is solely due to the in vitro capability of these enzymes to accept phytate as a substrate. Phytases have been studied intensively in recent years because of the great interest in such enzymes for reducing phytate content in animal feed and food for human consumption. They have a wide distribution in plants, microorganisms, and in some animal tissues. Due to several biological characteristics, such as substrate specificity, resistance to proteolysis and catalytic efficiency, bacterial phytases have considerable potential in commercial applications. In bacteria, phytase is an inducible enzyme and its expression is subjected to a complex regulation, but phytase formation is not controlled uniformly among different bacteria. It was suggested that phytase is not required for balanced growth of bacterial cells, but may be synthesised in response to a nutrient or energy limitation.

Bacterial phytase: potential application, in vivo function and regulation of its synthesis

The stepwise release of phosphate from phytate, the major storage form of phosphate in plant seeds and pollen, is initiated by a class of enzymes that have been collectively called phytases. The classification is solely due to the in vitro capability of these enzymes to accept phytate as a substrate. Phytases have been studied intensively in recent years because of the great interest in such enzymes for reducing phytate content in animal feed and food for human consumption. They have a wide distribution in plants, microorganisms, and in some animal tissues. Due to several biological characteristics, such as substrate specificity, resistance to proteolysis and catalytic efficiency, bacterial phytases have considerable potential in commercial applications. In bacteria, phytase is an inducible enzyme and its expression is subjected to a complex regulation, but phytase formation is not controlled uniformly among different bacteria. It was suggested that phytase is not required for balanced growth of bacterial cells, but may be synthesised in response to a nutrient or energy limitation.

The application of PCR in the detection of mycotoxigenic fungi in foods

It is estimated that 25 to 50 percent of the crops harvested worldwide are contaminated with mycotoxins. Because of the toxic and carcinogenic potential of mycotoxins, there is an urgent need to develop detection methods that are rapid and highly specific. The highly advanced physico-chemical methods for the analysis of mycotoxins in use, have the disadvantage that highly sophisticated clean-up and/or derivatization procedures must be applied. An alternative could be the detection of the mycotoxigenic moulds themselves, especially as molecular techniques have been introduced recently as powerful tools for detecting and identifying fungi. PCR methods for the detection of aflatoxigenic Aspergilli, patulin-producing Penicillum and trichothecene- as well as fumonisin-producing Fusaria strains have been described. The usefulness of the PCR methods developed so far to monitor quality and safety in the food an feed industry was already demonstrated. Thus, PCR may be applied to the screening of agricultural commodities for the absence of mycotoxin producers prior to or even after processing. Negative results in this assay indicate that a sample should be virtually free of mycotoxins. Only the positive samples left must be analyzed for the presence of mycotoxins using physico-chemical standard methods. This review does not only summarize the so far developed qualitative and quantitative PCR assays for the detection of mycotoxigenic fungi in agricultural commodities, foods and animal feeds, but describes also strategies to develop new specific PCR assays for such a detection.