蛹虫草高产胞外虫草素和虫草多糖的诱变育种

通过诱变获得高产胞外虫草素和虫草多糖的蛹虫草菌株.采用紫外线诱变(UV)、化学诱变(LiCl)、复合诱变(UV-LiCl) 3种方式对蛹虫草孢子进行诱变；发酵检测存活菌株的胞外虫草素和虫草多糖的含量.结果:以胞外虫草素为指标,3种诱变方式的最大正突变率分别为化学突变(29.2％)＞紫外突变(28.6％)＞复合诱变(26.5％)；以胞外多糖为指标,最大正突变率分别为紫外诱变(35.7％)＞复合诱变(33.3％)＞化学诱变(27.0％).紫外诱变突变株Z-5-1胞外虫草素产量达0.842g/L,比出发菌株高311％；紫外诱变突变株Z-4-7胞外虫草多糖产量达5.250g/L,比出发菌株高148％.在连续培养5代后,仍具有较好的遗传稳定性.紫外诱变能获得较高的蛹虫草正突变率,同时能获得高产虫草素、虫草多糖的突变株.

Enhanced production of extracellular cordycepin and polysaccharide in Cordyceps militaris by mutation breeding

The aim was to obtain high-yield strains of extracellular cordycepin and polysaccharide of Cordyceps militaris.Three kind of mutation way,ultraviolet radiation（UV）、lithium chloride（LiCl） and compound mutagenesis（UV-LiCl） were used to deal with the spores of Cordyceps militaris.Fermenting the survival strains and detecting their content of extracellular cordycepin and cordyceps polysaccharide.The results showed： the maximum positive mutation rate order of extracellular cordycepin was LiCl（29.2%） 〉 UV（28.6%） 〉 UV-LiCl（26.5%） respectively,and that of extracellular polysaccharide was UV（35.7%） 〉 UV-LiCl（33.3%） 〉 LiCl（27.0%）.The UV-induced mutant strain Z-5-1 had the highest extracellular cordycepin yield of 0.842g/L,which was 311% higher than that of the original strain.And the UV-induced mutant strain Z-4-7 had the highest extracellular Cordyceps polysaccharide production of 5.250g/L,which was 148% higher than that of the original strain.UV mutagenesis could obtain a higher positive mutation rate for Cordyceps militaris,while could produce good mutant strains with high-yield of extracellular cordycepin and extracellular cordyceps polysaccharide.