利用原生质体紫外诱变技术选育可常温发酵的中国被毛孢新菌株

中国被毛孢(Hirsutella sinensis)是天然冬虫夏草Cordyceps sinensis(Berk)Sacc.]的真正无性型,其生长温度低(低于20℃),生长缓慢(发酵周期长达20～30d),对人工发酵的技术条件要求很高,因而大大增加了工业化发酵生产的成本和技术难度。为了解决上述问题,实验中从天然冬虫夏草子座中分离到中国被毛孢菌株BS-1,并对其进行了原生质体紫外诱变处理。经过粗筛和精筛,从中选出一株可常温下(25～28℃)发酵、生长迅速(发酵周期4～5 d)、有效成分(甘露醇和腺苷)含量显著高于原始菌株的诱变株BS-5962。通过连续10代PDA斜面继代培养和摇瓶试验,以及连续3批的1t罐的中试试验,检查结果表明所得诱变株性状优异而稳定。可为降低中国被毛孢的液体深层发酵成本和技术难度提供一种有效的解决方案。

Breeding new strain of normal temperature fermented Hirsutella sinensis by UV induced mutagenesis

Hirsutella sinensis is the real anamorph of natural Cordyceps sinensis,it’s growth temperature is low(below 20℃) and the growth rate is also slow(the fermentation period is reached up to 20 - 30 d),which increase production cost and technical difficulty of industrial fermentation of Hirsutella sinensis.To solve above mentioned problems,a strain(BS-1) of Hirsutella sinensis was isolated from the stroma of a natural Cordyceps sinensis using a UV induced mutagenesis to treat protoplast of Hirsutella sinensis.The mutant BS-5962 was obtained through crude screen and careful screen.The growth period of this mutant is short(4 - 5 d of fermentation period) and the effective ingredient(mannitol and adenosine) contents are evidently higher than that of original strain.Most importantly,the new variant can be fermented at normal temperature(25 - 28 ℃).After culturing on PDA slants and in shaking bottles for 10 generations,and three-batch pilot plant tests at one-ton scale,the results showed that the mutant BS-5962 is an excellent strain with steady properties.This study provides an effective method for reducing production cost and solving the technical difficulty of industrial fermentation of Hirsutella sinensis.