Caracterização da diversidade de fungos filamentosos associados a esponjas marinhas e avaliação da produção de lacase = : Diversity of filamentous fungi associated with marine sponges and evaluation of laccase production / Diversity of filamentous fungi associated with marine sponges and evaluation of laccase production

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

06/09/2012

RESUMO

The ocean represents a promissing habitat in the search for new microorganisms, which may have the ability to produce enzymes of industrial interests different from that produced by their terrestrial counterparts. In this context, two samples of the marine sponge Dragmacidon reticulatum were collected on northern coast of São Paulo State, aiming at the characterization of fungal diversity by cultureddependent and -independent approaches as well as the evaluation of the production, characterization and expression of laccase enzyme gene. Regarding the cultivated portion of the samples, around 108 filamentous fungi were isolated, belonging to 64 different taxonomic groups (ribotypes), which were subjected to enzymatic activity assays. Polyphasic taxonomy approaches (macro- and microscopic, molecular - ITS/28S ribosomal genes - and MALDI TOF ICMS analyses) resulted in the characterization of 38 isolates distributed in 23 genera belonging to the phylum Ascomycota and one to the phylum Zygomycota, which were deposited in the Brazilian Collection of Micro-organisms from Environment and Industry (CBMAI). Among the isolates recovered one possible new species of Penicillium was identified. Enzymatic screening allowed the selection of two isolates identified as Nigrospora sp. CBMAI 1328 (0,30 U L-1) and Arthorpyrenia sp. CBMAI 1330 (0,40 U L-1), which were subjected to a new activity evaluation and expression (RT-PCR) with the induction of copper ions and the laccase genes characterization. The addition of copper ions in a concentration of 5 mM resulted in an increase in the enzymatic activities of CBMAI 1328 and CBMAI 1330 strains in 3,9X (25,2 U L-1) and 1,2X (9,0 U L-1) after 120h, respectively. The results of the expression of the laccase genes for CBMAI 1328 strain were the same found by induction with copper (expression increased in 5 mM after 120 h), however for CBMAI 1330 the higher expression was after 96 h without addition of copper. Results of laccase genes characterization revealed the existence of three possible putative new marine laccase genes. Regarding to the uncultured portion of the samples, from the DGGE and direct sequencing of the ITS rRNA gene and 18S gene approaches, was possible to identify seven species of fungi and one uncultured fungus from phylum Ascomycota and three species and one uncultured fungus from phylum Basidiomycota. For both approaches used the greatest diversity was achieved in the DR9 sample. Data derived from the present work highlight the importance of using polyphasic taxonomy as well as applying culturedependent and culture-independent methodologies (in parallel) in order to have a better and greater knowledge of the real diversity in environmental sample. These results expand the knowledge of fungi recovery from marine sponges and demonstrate the biotechnological potential of these micro-organisms.

ASSUNTO(S)

esponjas lacase fungos filamentosos taxonomia polifasica bibliotecas rrna its e 18s filamentous fungi sponges laccase polyphasic taxonomy its and 18s rrna libraries

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