Extracellular polysaccharides produced by the newly discovered source Scopularis spp.

Abstract

Background Microorganisms are better and cheaper sources for the production of polysaccharides. Therefore, there has been an increasing interest in isolating and identifying new microbial polysaccharides. Objective The aim of this study was to produce new extracellular polysaccharides, with better rheological properties and varied applications, from the newly discovered fungal strain Scopularis spp., using different carbon sources. Methods Fourier transform infrared spectroscopy, carbohydrate analysis, and thin layer chromatography were the methods used for the preliminary characterizing of the produced polysaccharides. Results Among the 10 examined carbon sources, fructose, raffinose, sucrose, and maltose were found to produce an appreciable amount of extracellular polysaccharides (0.90, 0.87, 0.86, and 0.74 g/l, respectively), whereas arabinose, lactose, and mannitol produced a minimal amount of extracellular polysaccharides (0.22, 0.17, 0.12 g/l, respectively). However, all the tested sugars enhanced the growth of the fungal strain. The analytical method proved that the polymer was a heteropolysaccharide with six sugar moieties, all different in their relative ratios from one carbon source to another. Glucose was found to be the most abundant monosugar in all the polymer samples. Galactose, rhamnose, and glucuronic acid also appeared on the thin layer chromatography plate. Conclusion A new extracellular heteropolysaccharide was produced from the new source, Scopularis spp. The produced polysaccharide contained glucose, galactose, glucuronic acid, rhamnose, and two other unidentified sugars as indicated from the thin layer chromatography plate.