Center for Biotechnology and Bioengineering, Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
Center for Pharmaceutical Science and Engineering, Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China.
Carbohydr Polym. 2022 Oct 15;294:119828. doi: 10.1016/j.carbpol.2022.119828. Epub 2022 Jul 5.
In this study, we explored a novel approach to enhancing the production and bioactivities of Ganoderma exopolysaccharides. The homologous phosphomannomutase gene (PMM1) was cloned and overexpressed in Ganoderma for the first time. As a result, the maximum production of exopolysaccharides by the PMM1 transformant was 1.53 g/L, which was 1.41-fold higher than of a wild-type (WT) strain in a 5-L bioreactor. The transcription levels of PMM1 and PMM2 increased 40.5- and 2.4-fold, respectively, whereas the value of the GDP-D-mannose pyrophosphorylase gene did not change significantly in this transgenic strain. Furthermore, the major exopolysaccharide fractions from PMM1 transformants contained higher amounts of mannose (56.5 % and 21.1 %) than those from a WT strain (26.7 % and 9.3 %). Moreover, the major fractions from PMM1 transformants exhibited stronger regulation effects on macrophage. In conclusion, this study is helpful for the efficient production and application of Ganoderma exopolysaccharides and facilitates an understanding of polysaccharide biosynthesis regulation.
在这项研究中，我们探索了一种提高灵芝胞外多糖产量和生物活性的新方法。首次在灵芝中克隆和过表达了同源磷酸甘露糖异构酶基因（PMM1）。结果，PMM1 转化子的胞外多糖最大产量为 1.53g/L，在 5L 生物反应器中比野生型（WT）菌株高 1.41 倍。PMM1 和 PMM2 的转录水平分别增加了 40.5 倍和 2.4 倍，而 GDP-D-甘露糖焦磷酸化酶基因的数值在该转基因菌株中没有明显变化。此外，PMM1 转化子的主要胞外多糖组分中甘露糖（56.5%和 21.1%）的含量高于 WT 菌株（26.7%和 9.3%）。此外，PMM1 转化子的主要组分对巨噬细胞表现出更强的调节作用。总之，这项研究有助于灵芝胞外多糖的高效生产和应用，并有助于理解多糖生物合成的调节。
