Effects of additives on cordycepin production using a Cordyceps militaris mutant induced by ion beam irradiation
Effects of additives on cordycepin production using a Cordyceps militaris mutant induced by ion beam irradiation
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DOI：
10.4314/ajb.v8i13.60983
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发表时间：
2009-07
影响因子：
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通讯作者：
S. Das;M. Masuda;A. Sakurai;M. Sakakibara
中科院分区：
文献类型：
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作者：
S. Das;M. Masuda;A. Sakurai;M. Sakakibara
为了获得具有较高虫草素产量的药用蘑菇蛹虫草可持续突变体，本研究采用高能离子束辐照技术。质子束照射成功后，获得了30类8-氮杂腺嘌呤耐药突变体和28类8-氮杂腺嘌呤耐药突变体，其中7类（A63-7、A63-8、A81-2、A81-6、G63-8、G81-3、G82-4）以其抑菌能力作为虫草素产量指标，被选为初步有希望的突变体。其中，优化条件下G81-3的虫草素产量最高，为6.84 g/l，高于对照的2.45 g/l（2.79倍）。此外，为了探讨不同添加剂对上述突变体表面液体培养虫草素产量的影响，以腺苷和甘氨酸为添加剂。在上述突变体优化条件下的培养基中，分别添加2、4、6、8和10 g/l腺苷。结果表明，使用6 g/l腺苷时虫草素产量最高，为8.57 g/l，比对照组（6.69 g/l）提高28.10%。这是迄今为止虫草素产量最高的一次报告。同样，其他浓度的结果也优于对照。葡萄糖时间过程显示，4 g/l腺苷处理的葡萄糖消耗最快，10 g/l处理的葡萄糖消耗最慢，培养时间最长。同样，在甘氨酸和酵母浸膏总量固定的情况下，以40/60、50/50、60/40、70/30、80/20和90/10的质量百分比（酵母浸膏/甘氨酸）分别添加甘氨酸和酵母浸膏。在相同的优化条件下，以固定的酵母浸膏浓度，分别以10%、20%和30%的质量分数添加甘氨酸。结果表明，在90/10比例下虫草素产量最高，为6.80 g/l，比对照（6.05 g/l）提高12.40%。体重百分比为70/30和80/20的虫草素产量也高于对照组，而其他菌种的虫草素产量低于对照组；特别是10%、20%和30%酵母浸膏的虫草素产量随甘氨酸浓度的增加呈负相关下降。从时间过程来看，酵母浸膏重量比为40% / 60%时葡萄糖消耗最快，重量比为30%时葡萄糖消耗最慢，培养时间最长。这些结果表明，离子束辐照和添加剂对虫草素的生产都有积极的影响，其中腺苷的影响要远远好于甘氨酸。同样明显的是，较高浓度的腺苷和甘氨酸对虫草素的产生有负面影响。
To obtain a sustainable mutant of the medicinal mushroom Cordyceps militaris with a higher cordycepin production, high-energy ion beam irradiation was applied in the present study. Upon successful irradiation by a proton beam, 30 classes of 8-azaadenine and 28 classes of 8-azaaguanine resistant mutants were obtained of which 7 classes (A63-7, A63-8, A81-2, A81-6, G63-8, G81-3, G82-4) were selected as initially promising mutants using their antibacterial ability as an index of cordycepin production. Among these mutants, G81-3 had the highest cordycepin production of 6.84 g/l using optimized conditions compared to that of the control of 2.45 g/l (2.79 times higher). In addition, to explore the influences of different additives on the cordycepin production using the above mutant in a surface liquid culture, adenosine and glycine were used as additives. In the culture medium under the previously optimized conditions for the said mutant, 2, 4, 6, 8 and 10 g/l adenosine were separately added. These results revealed the highest cordycepin production of 8.57 g/l when using 6 g/l adenosine was 28.10% higher than that of the control (6.69 g/l). This is a highest report of cordycepin production until now. Similarly, the results of other concentrations also superseded the control. The time course of glucose showed that the glucose consumption for the 4 g/l adenosine was the fastest, while that of 10 g/l was the slowest with the longest culture time among all the treatments. For the same purpose, glycine was used with yeast extract in weight percent ratios (yeast extract/glycine) of 40/60, 50/50, 60/40, 70/30, 80/20 and 90/10 under the condition that the total amount of glycine and yeast extract were fixed. Also, the glycine was separately added as 10, 20 and 30 weight percent of yeast extract in the culture medium having the same optimized conditions with a fixed yeast extract concentration. These results showed that the 90/10 ratio had the best cordycepin production of 6.80 g/l that was 12.40% higher versus the control (6.05 g/l). The cordycepin production of the 70/30 and 80/20 weight percent ratios were also higher than that of the control, while the others had a lower cordycepin production compared to that of the control; especially the cordycepin production with the 10, 20 and 30 weight percent yeast extracts inversely decreased in accordance with the used glycine concentration. Regarding the time course, the glucose consumption for the 40/60 weight percent ratio of yeast extract was the fastest, while that of the 30 weight percent was the slowest with the longest culture time among all the treatments. These results suggested that both the ion beam irradiation and additives had active influences on the cordycepin production and that adenosine had a much better influence than that of glycine. It was also evident that a higher concentration of both adenosine and glycine negatively affected the cordycepin production.