XXXV Reunião Anual da SBBqResumoID:9056


Isolation and Characterization of Polysaccharides from the Cell Wall of the Yeast Phaffia rhodozyma
BORGES, J. N.1; BONFIM, T. M. B. 1; SASSAKI, G. L2.; WAGNER, R.2; FONTANA, J. D. 1; WORANOVICZ-BARREIRA, S. M. 1

1Departamento de Farmácia, UFPR, PR; 2Departamento de Bioquímica, UFPR, PR.


The yeast Phaffia rhodozyma has been studied as a source of carotenoid pigments for diet formulation in aquaculture. Even though its carotenoid production is high, its application is limited due to the resistance of the cell wall, which is a barrier for its pigments biodisponibility. Yeast cells were cultivated using batch process and applied on cell wall polysaccharide research. The polysaccharides were obtained via aqueous extraction using cool water and 80ºC heated water and dimethyl sulfoxide. Afterwards, the fractions were purified via freeze-thawing, Fehling’s solution precipitation and Cetavlon precipitation. A α-D-glucan and a heteropolysaccharide were isolated and structurally investigated using 13C e 1H-NMR (including COSY, TOCSY and HMQC techniques), methylation analysis and monosaccharide composition determination. The α-D-glucan was isolated from dimethyl sulfoxide extraction followed by Fehling treatment and it’s structure was determined as a linear chain of α-D-(1→3)-glucopyranosyl units, alike the pseudonigeran isolated from Aspergillus niger and other polysaccharides from various yeast of the genus Schizosaccharomyces and Cryptococcus. The heteropolysaccharide was isolated from 80ºC heated water extraction followed by Cetavlon precipitation and showed a complex structure containing β-D-(1→4)-manopyranosyl units as main chain. Although its structure has not been completely elucidated, it was found that its side chains contained β-D-(1→4)-xylopyranosyl units along with D-mannose, D-galactose, D-glucose units. Besides these monosaccharides are found as non reducing ends as well.