Microbial degradation of extracellular polysaccharides released by a tropical strain of Staurastrum orbiculare (Zygnematophyceae)

Autor(es)

Giroldo‚ D. ; Vieira‚ A.A.H. ; Paulsen‚ B.S.

• Tipo de documento: Artigo Científico
• Fonte: PHYCOLOGIA; v. 44, n. 6, p. 671-677, 2005.

Resumo

The extracellular polysaccharide (EPS) released by a freshwater desmid, Staurastrum orbiculare (Zygnematophyceae), was characterized and their degradation by heterotrophic microbial populations was also evaluated. The EPS was purified by anion exchange column chromatography, the monosaccharide composition was determined by gas chromatography and the linkages of the monosaccharides by gas chromatographic analysis coupled with electron impact mass spectrometry. The EPS was mainly elated in one weak acid fraction, although a smaller strong acid fraction was also elated. The two fractions had similar composition and both of them were mainly composed of fucose, glucuronic acid, galactose, galacturonic acid, xylose, glucose, rhamnose and N-acetyl glucosamine. We monitored the entire EPS degradation, and also their components separately, during 35 days using pulse amperometric detection in a high-performance liquid chromatography. Fucose, galactose and especially glucose showed a faster degradation pattern than rhamnose and arabinose, whereas xylose and the total EPS showed an intermediate degradation pattern. The entire EPS was degraded in about 14 days evidencing S. orbiculare EPS as a high quality carbon source to the natural bacterial community of Barra Bonita reservoir. (AU)

• Processo FAPESP: 99/07766-0 - Produção e destino dos polissacarídeos extracelulares de origem algal em um reservatório eutrofizado do rio Tietê (estudo de processo)
• Beneficiário: Armando Augusto Henriques Vieira
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 99/01353-5 - Especificidade alga/bacteria vinculada a materia organica dissolvida excretada pelas algas planctonicas de agua doce.
• Beneficiário: Danilo Giroldo
• Modalidade de apoio: Bolsas no Brasil - Doutorado