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The influence of glucose concentration and other carbohydrates (monosaccharides: fructose, galactose, mannose; polyols: mannitol and sorbitol; disaccharides: lactose, sucrose and commercial sucrose; and industrial sugarcane molasses) were compared as sole carbon sources for the production of Botryosphaeran, an exopolysaccharide (EPS) produced by Botryosphaeria sp. The optimum glucose concentration for EPS production was 50 g l(-1). With the exception of mannitol, the fungus produced EPS on all carbon sources studied, with highest yields occurring with sucrose followed by glucose. All EPS showed exclusively glucose after acid hydrolysis and monosaccharide analysis. FTIR spectroscopy demonstrated the presence of beta-anomers indicating that all the EPS produced by Botryosphaeria sp. on the different carbon sources were essentially of the beta-D-glucan type.

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An exocellular β-(1→6)-D-glucan (lasiodiplodan) produced by a strain of Lasiodiplodia theobromae (MMLR) grown on sucrose was derivatized by sulfonation to promote anticoagulant activity. The structural features of the sulfonated β-(1→6)-D-glucan were investigated by UV-vis, FT-IR and (13)C NMR spectroscopy, and the anticoagulant activity was investigated by the classical coagulation assays APTT, PT and TT using heparin as standard. The content of sulfur and degree of substitution of the sulfonated glucan was 11.73% and 0.95, respectively. UV spectroscopy showed a band at 261 nm due to the unsaturated bond formed in the sulfonation reaction. Results of FT-IR and (13)C NMR indicated that sulfonyl groups were inserted on the polysaccharide. The sulfonated β-(1→6)-D-glucan presented anticoagulant activity as demonstrated by the increase in dose dependence of APTT and TT, and these actions most likely occurred because of the inserted sulfonate groups on the polysaccharide. The lasiodiplodan did not inhibit the coagulation tests.

Acidobacteria have been described as one of the most abundant and ubiquitous bacterial phyla in soil. However, factors contributing to this ecological success are not well elucidated mainly due to difficulties in bacterial isolation. Acidobacteria may be able to survive for long periods in soil due to protection provided by secreted extracellular polymeric substances that include exopolysaccharides (EPSs). Here we present the first study to characterize EPSs derived from two strains of Acidobacteria from subdivision 1 belonging to Granulicella sp. EPS are unique heteropolysaccharides containing mannose, glucose, galactose and xylose as major components, and are modified with carboxyl and methoxyl functional groups that we characterized by Fourier transform infrared (FTIR) spectroscopy. Both EPS compounds we identified can efficiently emulsify various oils (sunflower seed, diesel, and liquid paraffin) and hydrocarbons (toluene and hexane). Moreover, the emulsions are more thermostable over time than those of commercialized xanthan. Acidobacterial EPS can now be explored as a source of biopolymers that may be attractive and valuable for industrial applications due to their natural origin, sustainability, biodegradability and low toxicity.