Colletotrichum gloeosporioides biomass was submitted to ethanolic extraction (78 ºC, 12 h) to remove low molecular weight compounds followed by hot aqueous extraction (100 ºC, 4 h, 4x) to obtain polysaccharides. Consecutive freezing/thawing treatments of the aqueous extract yielded a soluble fraction in cold water that was separated on five components (PI to PV) by gel exclusion chromatography on Sepharose CL-6B. The PIV was homogeneous on HPSEC/RID, with apparent MW of 2.8 x 104 g mol-1, Mw/Mn 1.17, 100% of total sugar. The PIV was composed by galactose (61%), glucose (34%) and mannose (5%). 1H and 13C NMR analysis mono- and two-dimensional, homo- (COSY) and heteronuclear (HSQC and HMBC) showed that PIV is a heteropolysacharide with a main chain constituted by β-D-galactofuranosidic units (1→5) and (1→6) linked with some of the β-D-galactofuranosidic (1→6) units substituted in O-3 by α-D-glucopiranosidic residues. Cytotoxic assays (MTT) indicated that the viability of CHO-K1 cells, when exposed to different heteropolysaccharide concentrations, did not show significant differences when compared to the viability of the negative control (CN), in the experimental times of 24 and 48 hours. These results suggest the possibility of new cytotoxic assays in other normal cell lines as well as in tumor cells.

The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPS RT) and Mesorhizobium sp (EPS MR) are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose (~ 1%). Chemical analysis showed the presence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPS RT and EPS MR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, ¹H and 13C-NMR.

Viscosity of some polysaccharide solutions supports that these molecules can be applied in food sectors. Four exopolysaccharides (R1, R2, R3, R4) produced by different Rhizobium strains were selected. Sugar composition and differences in the uronic acid contents suggests that chemical structure of these molecules can vary when different culture conditions and strains are analyzed. The Power Law was the rheological model used to represent the experimental data of shear stress versus shear rate. All exopolysaccharides showed non-Newtonian behavior, with pseudoplastic characteristics. R1, R2 and R4 showed a slight increase in viscosity in the presence of 0,2 M NaCl.

A hexa-oligosaccharide was obtained by partial acid hydrolysis from botryosphaeran, an exopolysaccharide (EPS) β(1→3; 1→6)-D-glucan type, produced by the ascomyceteous fungus Botryosphaeria rhodina. The oligosaccharide was purified by gel filtration and charcoal-Celite column chromatography and the analysis was followed by HPAEC/PAD. The structure was determined by NMR spectroscopy and mass spectrometry, which showed that the oligosaccharide consists of six β-D-glucopiranosyl units O-6 substituted (gentiohexaose).

This article gives an overview of exopolysaccharides produced by fungi. The structural characterization of beta-D-(1->3) and beta-D-(1->3, 1->6)- glucans is discussed focusing on different chemical and physical procedures. The industrial applications are also considered mainly from the point of view of human health.

As glicoproteínas dos líquens Sticta tomentosa e Sticta damaecornis foram extraídas utilizando-se tampão específico e fracionadas pela adição crescente de sulfato de amônio. Dentre os diferentes cortes de saturação obtidos, as frações 30-80% de ambos os líquens foram eleitas objeto de estudo desta pesquisa. Métodos químicos e enzimáticos foram aplicados para a obtenção de oligossacarídeos N-ligados, que em seguida, foram derivatizados resultando em tirosinamida-oligossacarídeos. Após inserção do grupo cromóforo nas estruturas oligossacarídicas, os mesmos foram purificados por HPLC com detecção em 280 nm. Em relação ao líquen Sticta tomentosa, os cromatogramas revelaram a presença de dois picos com tempos de retenção de aproximadamente 11 e 18 minutos sugerindo a presença de dois diferentes oligossacarídeos N-ligados. O líquen Sticta damaecornis, seguindo as mesmas condições de purificação, apresentou em cromatografia quatro picos distintos com tempos de 11, 13, 18,2 e 18,4 minutos, respectivamente, sugerindo por sua vez a presença de quatro oligossacarídeos N-ligados diferentes.

The lichens Sticta tomentosa and Sticta damaecornis were extracted to obtain glycoproteins. The extracts were fractionated with 30-80% saturation (NH4)2SO4. The fractions were reduced, alkylated and after dialysis the material were digested with trypsin. The digests were dialyzed, freeze-dried and analyzed in reverse-phase high performance chromatography (RP-HPLC) based on the peptide hydrophobicity.N-linked oligosaccharides were removed from glycopeptides with PNGase A and analyzed by HPAEC-PAD that indicated the presence of several peaks between 12 to 17 min. The reducing oligosaccharides were reacted with NH4HCO3 to form oligosaccharides-glycosylamines and then derivatized with N-hydroxysuccinimidyl ester of Boc-tyrosine, resulting in tyrosinamide-oligosaccharides with sufficient hydrophobicity to facilitate RP-HPLC separation. RP-HPLC purification of asialyl tyrosinamide oligosaccharides from S. tomentosa showed two peaks eluted at 11 and 18 min. The asialyl tyrosinamide oligosaccharides from S. damaecornis eluted as four peaks at 11, 13, 18,2 and 18,4 min. The components that eluted at 11 min for both lichens showed the same monosaccharide composition.