Estudo das enzimas produzidas por Trichoderma longibrachiatum responsaveis pela degradação de materiais celulosicos

AUTOR(ES)
DATA DE PUBLICAÇÃO

1992

RESUMO

A total of 626 microorganisms were isolated from samples of soil and biodegraded cellulosic material collected from various areas in Brazil. One mesophilic fungus which was identified as Trichoderma longibrachiatum was selected. The production and characterization of the enzymes, which promote the degradation of cellulosic materials, were studied. Relatively pure celluloses and agrindustrial residues were used as carbon sources. The highest filter paper rnicrocrystalline cellulose and carboxymetilcellulose hydrolysis activities were obtained following growth of the microorganism in Solka-Floc, whereas β-g1ucosidase and xylanase exhibited the greatest activities after growth in sugar cane bagasse. The activity of the cellulolytic system determined as filter paper hydrolysis showed pH optimum at the 4.6-5.0 intervals and mantained 87% of its original activity after 24 hours incubation at the pH range 4.4-5.0. The optimum temperature for activity was 55 º C and after 1 hour and 24 hours incubation at this temperature de enzyme kept 70% and 15% respectively of its activity. The enzymatic system produced by the fungus was partially purified after DEAE-Sephadex A-50 column chromatography and Sephadex G-100 gel filtration. the molecular weight of some of the components was aproximately estimated getting a 44 kDa β-glicosidase 14 and 16 kDa xylanases and a 60 kDa exoglucanase A mutant was obtained after exposition of the isolated strain to U. V. light. Its morphological characteristics were different from the original strain and its enzymatic production was lower indicating a possible alteration in the secretory system

ASSUNTO(S)

celulose biotecnologia

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