求翻译：【摘 要】 目的：通过实验探索微量元素硒、钙、镁离子对甘露聚糖肽发酵的影响。方法：将不同浓度的硒、钙、镁离子添加到甘露聚糖肽发酵培养液中，在37℃下培养不同时间后取样，测定菌落数和发酵液中游离的硒、钙、镁浓度的变化。结果：发酵过程中能促进甘露聚糖肽与微量元素结合的的最佳浓度分别为：亚硒酸钠20μg.mL-1，氯化钙0.05g.mL-1，硫酸镁0.05g.mL-1。结论：在发酵液中加入适量的硒、钙、镁离子,能促进对甘露聚糖肽与他们的结合。是什么意思？

The "Summary" purpose: study on the trace element selenium, calcium and magnesium ion on the effect of Mannan glycopeptide fermentation. To: different concentrations of selenium, calcium and magnesium ions to mannatide in fermentation liquid, at 37 ° c after training under different time sampling, determination of number of colonies, and in fermentation of selenium, calcium and magnesium concentration of free. Results: during fermentation can promote mannatide best in combination with trace elements concentration are: 20 μ g.mL-1 sodium selenite, calcium chloride 0.05g.mL-1, magnesium sulfate 0.05g.mL-1. Conclusion: in the broth and add appropriate amount of selenium, calcium and magnesium ions, can promote mannatide and their combination.