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
复制标题
塔克拉玛干沙漠Aureobasidium melanogenum 13-2产生的大分子普鲁兰多糖及其抗逆性作用
DOI：
10.1016/j.ijbiomac.2019.05.190
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发表时间：
2019-08-15
影响因子：
8.2
通讯作者：
Chi, Zhen-Ming
中科院分区：
文献类型：
--
作者：
Jiang, Hong;Chen, Tie-Jun;Chi, Zhen-Ming
从塔克拉玛干沙漠中分离到一株产黑素短梗霉13-2，该菌株具有较高的胞外多糖（EPS）产量。在最佳条件下，摇瓶发酵5d，胞外多糖产量可达73.25 ± 2.3g/L。在10 L发酵罐中，该菌株在120 h内可产生78.05 ± 3.5 g/L的EPS。对Sigma普鲁兰多糖标准品和A. melanogenum 13-2的胞外多糖几乎完全相同，纯化的胞外多糖可以被普鲁兰酶活性水解，证明纯化的胞外多糖是普鲁兰多糖。纯化的普鲁兰多糖的分子量（Mw）估计为7.703 × 10（5）g/moL。普鲁兰合成酶基因（PUL 1）的破坏使突变体DAG 27失去合成任何普鲁兰的能力。突变株DAG 27比野生型菌株13-2对紫外线辐射、高浓度氯化钠、热处理、过氧化氢强氧化和干燥更敏感，表明产生的普鲁兰在酵母细胞抵抗各种胁迫方面发挥重要作用。这是首次从沙漠中获得的酵母菌株能产生如此高水平的普鲁兰多糖，而且所产生的普鲁兰多糖对普鲁兰多糖产生菌有明显的保护作用。(C)2019由Elsevier B. V.出版
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 x 10(5) 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 time to show that the yeast strain obtained from the desert could produce such high level pullulan and the produced pullulan had an obviously protective effect on its producer. (C) 2019 Published by Elsevier B.V.