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以菌丝体干质量为评价指标,对冬虫夏草菌(Cordyceps sinensis)CS.SYSU-Ⅱ在5 L发酵罐中的发酵条件进行优化。在单因素试验基础上,选取搅拌转速、通气量和装料系数,采用3因素3水平的正交设计试验,得出最佳发酵条件并验证,最后扩大至20 L发酵罐。结果表明,冬虫夏草菌CS.SYSU-Ⅱ在5 L发酵罐中培养6 d的最佳发酵条件为搅拌转速220 r/min、通气量2.0 vvm和装料系数60%,在此条件下进行验证试验,菌丝体干质量能达到(19.85±0.52)g/L。扩大至20 L发酵罐,可得菌丝体干质量为(16.78±0.06)g/L,发酵结果能达到5 L发酵罐的85%。通过比较摇床与5 L发酵罐的生长曲线,发现p H值能反映菌丝体干质量的变化趋势,可将p H值的变化规律作为发酵结束的判断依据。
The mycelial dry mass was used as the evaluation index to optimize the fermentation conditions of Cordyceps sinensis CS.SYSU-Ⅱ in 5 L fermenter. Based on the single-factor experiment, the optimum fermentation conditions were obtained and validated by 3-factor-3 orthogonal design with stirring speed, aeration rate and loading coefficient. Finally, the fermentation was extended to 20 L fermenter. The results showed that the optimum fermentation conditions of Cordyceps sinensis CS.SYSU-Ⅱ cultured in 5 L fermenter for 6 d were the stirring speed of 220 r / min, the aeration rate of 2.0 vvm and the loading coefficient of 60% Mycelium dry mass can reach (19.85 ± 0.52) g / L. Expanding to 20 L fermenter, the dry mass of mycelium was (16.78 ± 0.06) g / L and the fermentation result could reach 85% of 5 L fermenter. By comparing the growth curve of shaker and 5 L fermenter, it was found that p H value can reflect the trend of mycelial dry mass, which can be used to judge the change of p H value as the end of fermentation.