Aproveitamento de subprodutos agroindustriais para a produção de amilases fúngicas: estudo de parâmetros fermentativos e caracterização das enzimas

Pós-graduação em Microbiologia Agropecuária - FCAV

Desenvolvimento de novas tecnologias para produção de xarope de glicose a partir do amido

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Probióticos na alimentação de tilápias do Nilo: desempenho produtivo, hematologia e imunologia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Produção e avaliação das aplicações de enzimas quitinolíticas e queratinolíticas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Rhizoctonia solani AG-1: estrutura genética, etiologia e evolutibilidade nos agroecossitemas Brachiaria spp. e arroz na Colômbia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mucorales de solo contaminado com metais pesados na região do pólo cerâmico de Santa Gertrudes, SP: ocorrência e capacidade de biossorção de chumbo e zinco

Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC

Avaliação da permeação cutânea in vitro de sistemas nanoestruturados contendo ácido kójico

O processo de envelhecimento origina uma série de alterações na pele, dentre elas as o estresse oxidativo e as discromias. O ácido kójico tem a capacidade de atuar no tratamento do envelhecimento cutâneo em virtude de sua atividade ferro-quelante e de promover a despigmentação da pele devido inibir a tirosinase, impedindo a formação da melanina. Sistemas de liberação controlada de substâncias ativas, como os sistemas líquido-cristalinos, tem a propriedade de modular a permeação cutânea de fármacos, além de melhorar a sua ação. O presente trabalho tem como objetivo desenvolver e caracterizar um sistema líquido cristalino constituído por água e isonomanoato de cetoestearila (óleo), e estabilizado com o tensoativo álcool cetílico etoxilado e propoxilado contendo ácido kójico, avaliando sua permeação cutânea in vitro. A partir da construção de um diagrama de fases, foram selecionadas três formulações caracterizadas microscopicamente como CLs de fase hexagonal, denominada de A (35% O, 50 % T e 15% A), B (30% O, 50 % T e 20% A) e C (20% O, 50% T e 30% A), para prosseguir com o estudo, que consistiu na incorporação do ácido kójico na concentração de 2% e a realização dos ensaios de textura, bioadesão, reologia e de permeação e retenção cutânea in vitro. O ensaio de textura demonstrou que a formulação B com valores intermediários de água e fase oleosa apresentou valores intermediários de dureza, compressibilidade e adesividade, ideais para aplicação tópica. O ensaio de bioadesão mostrou que com o acréscimo de água na fórmula a força bioadesiva aumentou, o que pode melhorar a fixação do produto na pele do usuário. O ensaio reológico evidenciou que há aumento da viscosidade com acréscimo de água na formulação e que os sistemas analisados tratavam-se de fluidos pseudoplásticos com tixotropia tempo dependente... (Resumo completo, clicar acesso eletrônico abaixo)

Synthesis of Structured Lipids by Enzymatic Interesterification of Milkfat and Soybean Oil in a Basket-Type Stirred Tank Reactor

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Continuous enzymatic interesterification of milkfat with soybean oil produces a highly spreadable product rich in polyunsaturated fatty acids

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Screening, immobilization and utilization of whole cell biocatalysts to mediate the ethanolysis of babassu oil

The screening. biomass growth of lipase-producing fungus isolated from different sources and available at URM (University Recife Mycologia). as well as, the immobilization and utilization of the whole cells for the transesterification of babassu oil were investigated. Rhizopus oryzae (URM 3231, 4692), Mucor circinelloides (URM 4140, 4182) and Penicillium citrinum URM 4216 were considered to be good intracellular lipase producers whereas those from Mucor hiemalis URM 4144 and Mucor piriformis URM 4145 were weaker. Fungi biomass containing high lipase activities was immobilized on different biomass support particles (BSPs) and with the exception of Penicillium citrinum URM 4216 all the other fungi strains exhibited high lipase activity (20-50 Ug(-1)) when immobilized in situ using polyurethane foam particles. Transesterification activities of the immobilized whole cells were evaluated in the ethanolysis reaction with babassu oil and the highest performance was attained by M. circinelloides URM 4182 giving 83.22 +/- 3.68% ester yield in less than 96 h reaction. The biocatalyst operational stability was also assessed and an inactivation profile was found to follow the Arrhenius model, revealing values of 26 days and 2.6 x 10(-2)day(-1), for half-life and a deactivation coefficient, respectively. The purified product (biodiesel) exhibited viscosity (6.63 cSt) close to the value to attend specifications by the ASTM 06751 to be used as biofuel. Results are favorable compared with data already reported in the literature and demonstrated that M. circinelloides URM 4182 whole cells is a cheaper biocatalyst that can be used in the biodiesel synthesis. (C) 2012 Elsevier B.V. All rights reserved.

Comparative Genome Analysis of Trichophyton rubrum and Related Dermatophytes Reveals Candidate Genes Involved in Infection

The major cause of athlete's foot is Trichophyton rubrum, a dermatophyte or fungal pathogen of human skin. To facilitate molecular analyses of the dermatophytes, we sequenced T. rubrum and four related species, Trichophyton tonsurans, Trichophyton equinum, Microsporum canis, and Microsporum gypseum. These species differ in host range, mating, and disease progression. The dermatophyte genomes are highly colinear yet contain gene family expansions not found in other human-associated fungi. Dermatophyte genomes are enriched for gene families containing the LysM domain, which binds chitin and potentially related carbohydrates. These LysM domains differ in sequence from those in other species in regions of the peptide that could affect substrate binding. The dermatophytes also encode novel sets of fungus-specific kinases with unknown specificity, including nonfunctional pseudokinases, which may inhibit phosphorylation by competing for kinase sites within substrates, acting as allosteric effectors, or acting as scaffolds for signaling. The dermatophytes are also enriched for a large number of enzymes that synthesize secondary metabolites, including dermatophyte-specific genes that could synthesize novel compounds. Finally, dermatophytes are enriched in several classes of proteases that are necessary for fungal growth and nutrient acquisition on keratinized tissues. Despite differences in mating ability, genes involved in mating and meiosis are conserved across species, suggesting the possibility of cryptic mating in species where it has not been previously detected. These genome analyses identify gene families that are important to our understanding of how dermatophytes cause chronic infections, how they interact with epithelial cells, and how they respond to the host immune response. IMPORTANCE Athlete's foot, jock itch, ringworm, and nail infections are common fungal infections, all caused by fungi known as dermatophytes (fungi that infect skin). This report presents the genome sequences of Trichophyton rubrum, the most frequent cause of athlete's foot, as well as four other common dermatophytes. Dermatophyte genomes are enriched for four gene classes that may contribute to the ability of these fungi to cause disease. These include (i) proteases secreted to degrade skin; (ii) kinases, including pseudokinases, that are involved in signaling necessary for adapting to skin; (iii) secondary metabolites, compounds that act as toxins or signals in the interactions between fungus and host; and (iv) a class of proteins (LysM) that appear to bind and mask cell wall components and carbohydrates, thus avoiding the host's immune response to the fungi. These genome sequences provide a strong foundation for future work in understanding how dermatophytes cause disease.

Characterization of aflatoxigenic and non-aflatoxigenic strains of Aspergillus section Flavi isolated from corn grains of different geographic origins in Brazil

Aflatoxins can cause great economic losses and serious risks to humans and animals health. The largest aflatoxin producers belong to Aspergillus section Flavi and can occur naturally in food commodities. Studies showed that molecular tools as well as the type of sclerotia produced by the strains could be helpful for identification of Aspergillus species and could be correlated with levels of toxin production. The purpose of this work was to characterize the genetic diversity using AFLP technique, the type of sclerotia and the ability of aflatoxin production by isolated strains from corn of different origins in Brazil, and to verify whether qPCR based on aflR and aflP genes is appropriate for estimating the level of aflatoxin production. All the 75 strains were classified as A. flavus and the AFLP technique showed a wide intraspecific variability within them. Regarding sclerotia production, 34% were classified as S and 66% as L type. Among the aflatoxin-producers, 52.8% produced aflatoxin B-1, while 47.2% aflatoxins B-1 and B-2. Statistical analysis showed no correlation between sclerotia production and aflatoxigenicty, and no correlation between the phylogenetic clusters and aflatoxin production. Concerning the relative expression of aflR and aflP, Pearson's correlation test demonstrated low positive correlation between the expression of the aflR and aflP genes and the production of AFB(1) and AFB(2), but showed high positive correlation between aflR and aflP expression. In contrast to the other reference strains, A. oryzae ATCC 7282 showed no amplification of aflR and aflP. The results highlight the need for detection of reliable and reproducible markers with a high positive correlation with aflatoxin production.

Characterization of a thermostable extracellular tannase produced under submerged fermentation by Aspergillus ochraceus

Background: Tannases are enzymes that may be used in different industrial sectors as, for example, food and pharmaceutical. They are obtained mainly from microorganisms, as filamentous fungi. However, the diversity of fungi stays poorly explored for tannase production. In this article, Aspergillus ochraceus is presented as a new source of tannase with interesting features for biotechnological applications. Results: Extracellular tannase production was induced when the fungus was cultured in Khanna medium with tannic acid as carbon source. The extracellular tannase was purified 9-fold with 2% recovery and a single band corresponding to 85 kDa was observed in SDS-PAGE. The native apparent molecular mass was estimated as 112 kDa. Optima of temperature and pH were 40 degrees C and 5.0, respectively. The enzyme was fully stable from 40 degrees C to 60 degrees C during 1 hr. The activity was enhanced by Mn2+ (33-39%) and NH4+ (15%). The purified tannase hydrolyzed tannic acid and methyl gallate with Km of 0.76 mM and 0.72 mM, respectively, and Vmax of 0.92 U/mg protein and 0.68 U/mg protein, respectively. The analysis of a partial sequence of the tannase encoding gene showed an open read frame of 567 bp and a sequence of 199 amino acids were predicted. TLC analysis revealed the presence of gallic acid as a tannic acid hydrolysis product. Conclusion: The extracellular tannase produced by A. ochraceus showed distinctive characteristics such as monomeric structure and activation by Mn2+, suggesting a new kind of fungal tannases with biotechnological potential. Further, it was the first time that a partial gene sequence for A. ochraceus tannase was described.

Polygalacturonase Gene Expression in Ripe Melon Fruit Supports a Role for Polygalacturonase in Ripening-Associated Pectin Disassembly

Ripening-associated pectin disassembly in melon is characterized by a decrease in molecular mass and an increase in the solubilization of polyuronide, modifications that in other fruit have been attributed to the activity of polygalacturonase (PG). Although it has been reported that PG activity is absent during melon fruit ripening, a mechanism for PG-independent pectin disassembly has not been positively identified. Here we provide evidence that pectin disassembly in melon (Cucumis melo) may be PG mediated. Three melon cDNA clones with significant homology to other cloned PGs were isolated from the rapidly ripening cultivar Charentais (C. melo cv Reticulatus F1 Alpha) and were expressed at high levels during fruit ripening. The expression pattern correlated temporally with an increase in pectin-degrading activity and a decrease in the molecular mass of cell wall pectins, suggesting that these genes encode functional PGs. MPG1 and MPG2 were closely related to peach fruit and tomato abscission zone PGs, and MPG3 was closely related to tomato fruit PG. MPG1, the most abundant melon PG mRNA, was expressed in Aspergillus oryzae. The culture filtrate exponentially decreased the viscosity of a pectin solution and catalyzed the linear release of reducing groups, suggesting that MPG1 encodes an endo-PG with the potential to depolymerize melon fruit cell wall pectin. Because MPG1 belongs to a group of PGs divergent from the well-characterized tomato fruit PG, this supports the involvement of a second class of PGs in fruit ripening-associated pectin disassembly.

Characterization of Recombinant Rhamnogalacturonan α-l-Rhamnopyranosyl-(1,4)-α-d-Galactopyranosyluronide Lyase from Aspergillus aculeatus1 : An Enzyme That Fragments Rhamnogalacturonan I Regions of Pectin

The four major oligomeric reaction products from saponified modified hairy regions (MHR-S) from apple, produced by recombinant rhamnogalacturonan (RG) α-l-rhamnopyranosyl-(1,4)-α-d-galactopyranosyluronide lyase (rRG-lyase) from Aspergillus aculeatus, were isolated and characterized by 1H-nuclear magnetic resonance spectroscopy. They contain an alternating RG backbone with a degree of polymerization of 4, 6, 8, and 10 and with an α-Δ-(4,5)-unsaturated d-galactopyranosyluronic acid at the nonreducing end and an l-rhamnopyranose at the reducing end. l-Rhamnopyranose units are substituted at C-4 with β-galactose. The maximum reaction rate of rRG-lyase toward MHR-S at pH 6.0 and 31°C was 28 units mg−1. rRG-lyase and RG-hydrolase cleave the same alternating RG I subunit in MHR. Both of these enzymes fragment MHR by a multiple attack mechanism. The catalytic efficiency of rRG-lyase for MHR increases with decreasing degree of acetylation. Removal of arabinose side chains improves the action of rRG-lyase toward MHR-S. In contrast, removal of galactose side chains decreased the catalytic efficiency of rRG-lyase. Native RG-lyase was purified from A. aculeatus, characterized, and found to be similar to the rRG-lyase expressed in Aspergillus oryzae.