无机氮源对出芽短梗霉发酵普鲁兰多糖分子量的影响

Effects of Inorganic Nitrogen Sources on the Molecular Weight of Pullulan Produced by Aureobasidium pullulans

摘要:

以出芽短梗霉（Aureobasidium pullulans）CGMCC No.11062为出发菌株，研究五种无机氮源对普鲁兰多糖产量、结构、纯度及分子量的影响。结果表明：无机氮源种类对普鲁兰多糖产量和分子量产生显著影响，未影响普鲁兰多糖结构和纯度。其中，以硫酸铵（1.5 g/L）为唯一氮源时普鲁兰多糖产量达到32.84 g/L，重均分子量（Weight-average Molecular Weight，Mw）最大，为799823 ku。硫酸铵浓度对普鲁兰多糖的产量和分子量影响显著，而未显著影响普鲁兰多糖结构。随着硫酸铵浓度的增加，普鲁兰多糖产量和分子量同时增加；当硫酸铵浓度为1.5 g/L时，普鲁兰多糖的产量出现最大值，为32.45 g/L；而当硫酸铵浓度为2.1 g/L，普鲁兰多糖重均分子量（Mw）最大，达到1236958 ku。所有制得的普鲁兰多糖纯度在95%~99%之间。这些研究可为不同分子量普鲁兰多糖生产提供技术指导。

Abstract:

The effects of five types of inorganic nitrogen sources on the yield, structure, purity, and molecular weight of pullulan were studied using Aureobasidium pullulans CGMCC No. 11062 as the parental strain. The results showed that the yield and molecular weight of pullulan were significantly influenced by the types of inorganic nitrogen source, whereas the structure and purity of pullulan were not affected. When ammonium sulfate (1.5 g/L) was used as the sole nitrogen source, the yield of pullulan was 32.84 g/L, and the maximum weight-average molecular weight (Mw) of pullulan (799823 ku) was obtained. Furthermore, the yield and molecular weight of pullulan were significantly influenced by the concentration of ammonium sulfate, which did not significantly affect the structure of pullulan. With increasing concentration of ammonium sulfate, the yield and molecular weight of pullulan increased simultaneously. The maximum yield of pullulan (32.45 g/L) was reached at 1.5 g/L ammonium sulfate, and the peak Mw of pullulan (1236058 ku) was obtained at 2.1 g/L ammonium sulfate. The purity of pullulan produced from all experiments was between 95% and 99%. These studies could provide technical guidance for the production of pullulan with different molecular weights.