Macromolecular pullulan produced by Aureobasidium melanogenum 13-2 isolated from the Taklimakan desert and its crucial roles in resistance to the stress treatments.

Macromolecular pullulan produced by Aureobasidium melanogenum 13-2 isolated from the Taklimakan desert and its crucial roles in resistance to the stress treatments. Int J Biol Macromol. 2019 May 27;: Authors: Jiang H, Chen TJ, Chi Z, Hu Z, Liu GL, Sun Y, Zhang SH, Chi ZM Abstract A novel yeast strain Aureobasidium melanogenum 13-2 isolated from the Taklimakan desert was found to be able to produce a high level of extracellular polysaccharide (EPS). Under the optimal conditions, the yeast strain could yield 73.25 ± 2.3 g/L of EPS within 5 days at a flask level. During a 10-liter fermentation, the yeast strain could produce 78.05 ± 3.5 g/L of EPS within 120 h. The FT-IR spectra of the standard pullulan from Sigma and the purified EPS produced by A. melanogenum 13-2 were almost identical and the purified EPS could be actively hydrolyzed by a pullulanase, demonstrating that the purified EPS was pullulan. The molecular weight (Mw) of the purified pullulan was estimated to be 7.703 × 105 g/moL. Disruption of a pullulan synthase gene (PUL1) made a mutant DAG27 lose the ability to synthesize any pullulan. The mutant DAG27 was more sensitive to radiation of UV light, high NaCl concentration, heat treatment, strong oxidation of H2O2 and desiccation than its wild type strain 13-2, suggesting that the produced pullulan could play an important role in resistance of the yeast cells to various stresses. This was the first t...
Source: International Journal of Biological Macromolecules - Category: Biochemistry Authors: Tags: Int J Biol Macromol Source Type: research