Microbiologia

URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11840

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Data inicial: 2001Data final: 2008Tem arquivos: SimAssunto: search.filters.subject.Pectinases

Resultados da Pesquisa

Agora exibindo 1 - 4 de 4
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    Isolation of recombinant strains with enhanced pectinase production by protoplast fusion between Penicillium expansum and Penicillium griseoroseum
    (Brazilian Journal of Microbiology, 2007-01) Queiroz, Marisa Vieira de; Lana, Taís Guimarães; Gonçalves, Daniel Bonoto; Araújo, Elza Fernandes de; Brito, Admilson Toscano Ribeiro de; Varavallo, Maurilio Antonio
    Protoplast fusion between complementary auxotrophic and morphological mutant strains of Penicillium griseoroseum and P. expansum was induced by polyethylene glycol and calcium ions (Ca2+). Fusant strains were obtained in minimal medium and a prototrophic strain, possibly diploid, was chosen for haplodization with the fungicide benomyl. Different recombinant strains were isolated and characterized for occurrence of auxotrophic mutations and pectinolytic enzyme production. The fusant prototrophic did not present higher pectinase production than the parental strains, but among 29 recombinants analyzed, four presented enhanced enzyme activities. The recombinant RGE27, which possesses the same auxotrophic and morphologic mutations as the P. griseoroseum parental strain, presented a considerable increase in polygalacturonase (3-fold) and pectin lyase production (1.2-fold).
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    Production of pectin lyase by Penicillium griseoroseum in bioreactors in the absence of inducer
    (Brazilian Journal of Microbiology, 2001-04) Passos, Flávia Maria Lopes; Passos, Frederico José Vieira; Silva, Daison Olzany; Piccoli-Valle, Roberta Hilsdorf
    Penicillium griseoroseum was grown in bioreactors on mineral medium supplemented with yeast extract and sucrose. The influence of inoculum and carbon source concentrations, aeration and pH on pectin lyase (PL) production, as well as the capacity of P. griseoroseum to produce PL when grown on sugar cane syrup as carbon source were evaluated. Inoculum concentration did not influence PL production. Production was higher in non-aerated than in aerated medium. The best results were obtained using 60 mM sucrose at pH 6.3-7.2. Production using cane syrup 25% (v/v), without yeast extract supplement, was equal to that obtained under the conditions cited above.
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    Differential expression of plg genes from Penicillium griseoroseum: plg1 a pectinolytic gene is expressed in sucrose and yeast extract
    (Journal of Applied Microbiology, 2008-04-22) Bazzolli, D.M.S.; Ribon, A. de O.B.; Reis, K.C.P.; Queiroz, M.V. de; Araújo, E.F. de
    To study the regulation of the plg1 and plg2 genes of Penicillium griseoroseum, in order to identify the industrial potential of their products in alternative carbon sources that are cheaper and widely available in Brazil. RT-PCR and Northern blot were used to investigate if plg1 and plg2 expression is under influence of catabolic repression, ambient pH and cAMP. Results demonstrated that the genes were differentially regulated depending on the carbon sources in the culture medium and pH. Sucrose, a noninducing carbon source of the pectinolytic system, was able to promote plg1 transcription but only when yeast extract was added into the culture medium. The plg genes are differentially expressed. The plg1 gene is more attractive for industrial use due to its expression in alternative carbon sources like sucrose and yeast extract. In recent years, industries have been trying to replace the toxic conventional treatments employed in these processes by more eco-friendly enzyme treatment. Alternative carbon sources will be tested with the aim to reduce the costs associated to pectin lyase production in Brazil.
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    Easy detection of green fluorescent protein multicopy transformants in Penicillium griseoroseum
    (Genetics and Molecular Research, 2004-12-21) Lopes, Francis J.F.; Araújo, Elza F. de; Queiroz, Marisa V. de
    Penicillium griseoroseum, a deuteromycete fungus producer of pectinolytic enzymes, was transformed with a gene encoding for green fluorescent protein (GFP). The selection of transformants was based on the homologous nitrate reductase gene (niaD). Protoplasts of a P. griseoroseum Nia mutant (PG63) were co-transformed with the plasmids pNPG1 and pAN52-1-GFP. The plasmid pNPG-1 carries the homologous niaD gene and pAN52-1-GFP carries the SGFP-TYG version of GFP. The highest transformation efficiency (102 transformants/µg of pNPG1) resulted from the utilization of equimolar amounts of transforming and co-transforming vectors. Analysis of pAN52-1-GFP insertions into the genomic DNA of the transformants revealed single and multiple copy integrations. The transformants possessing a single copy of the gfp gene showed a low level of fluorescence, whereas multicopy transformants displayed strong fluorescence under visualization with fluorescent light. The transformants showing high expression of the gfp gene had the normal mycelia pigmentation altered, displaying a bright green-yellowish color, visible with the naked eye on the plates, without the aid of any kind of fluorescent light or special filter set.