中文摘要：

旨在评价紫外线（UV）和亚硝基胍（NTG）诱变处理对菌株FGM发酵提取黄芪多糖的影响。分别用适量UV、NTG、UV＋NTG诱变处理对数生长期的益生菌株FGM,筛选生长性能较好的诱变株发酵中药黄芪,水提醇沉发酵产物中的粗多糖,苯酚―硫酸法测定多糖质量分数。结果显示,UV处理90s得到的诱变菌株U90发酵黄芪后,产物中多糖质量分数比其他诱变剂量较高,为235.51mg/g,与诱变前相比增加58.13%;1.0g/L的NTG处理菌株10min后,得到的诱变株N1-1发酵黄芪后,产物中多糖质量分数比其他剂量高,为161.2mg/g,与诱变前比较增加10.64%;UV照射10s后,再用1.0g/L的NTG处理10min,得到的诱变菌株UN10-1发酵黄芪后,产物中的多糖质量分数为293.39mg/g,较诱变前增加了94.99%;UV照射10~120s所得的菌株发酵黄芪后产物中多糖质量分数均呈升高趋势,而NTG处理所得菌株发酵黄芪后产物中多糖质量分数变化无规律性。由此可见,UV和NTG诱变均有改善益生菌株FGM发酵提取黄芪多糖的作用,但NTG改善菌株发酵性能不明显,适量UV照射结合一定浓度NTG诱变所得的菌株发酵提取黄芪多糖的性能优于UV和NTG单独作用。

英文摘要：

The objective of this study is to evaluate the effects of ultraviolet（UV）and nitrosoguanidine（NTG）on the polysaccharides extraction of Astragalus membranaceus fermented with probiotic strain FGM.The probiotic strain FGM in logarithmic phase was treated by UV,NTG and UV plus NTG,respectively.The stain with outstanding growth performance was used to ferment A.membranaceus,the polysaccharides in fermented product were obtained by water extraction and alcohol precipitation.The polysaccharides mass fraction was determined with the method of phenol-sulfuric acid.A.membranaceus was fermented with Strain U90（FGM treated by UV radiation for 90s）,the massfraction of polysaccharides in fermentation product was 235.51mg/g,higher than any other UV treatment,raised by 58.13% compared with the original strain FGM＇s;strain N1-1（1.0g/L NTG treated for 10min）,achieved higher mass fraction of polysaccharides in fermentation product which were 161.2mg/g,raised 10.64%;strain UN10-1（UV radiation for 10 scombined with 1.0g/L NTG treating for 10min）,which mass fraction of polysaccharides in fermentation product was 293.39 mg/g,obviously high than that of U90 and N1-1,raised by 94.99% compared with FGM＇s.The polysaccharide mass fraction increased after the strain FGM was radiated with UV for 10-120 s.There is not any regular pattern on the strain FGM treated with NTG.In conclusion,the effect of UV on polysaccharide extraction in A.membranaceus by fermentation is positive,NTG showed a bilateral effect on the polysaccharide extraction of the herb with fermentation.The fermented polysaccharide extraction of A.membranaceus was improved significantly after the strain FGM treated jointly with optimal dose UV radiation and NTG,which is better than separate treatment of them.