氮源对蛹虫草生长及类胡萝卜素产生的影响

Effect of nitrogen sources on the growth and carotenoid production in Cordyceps militaris

摘要:

【背景】蛹虫草是一种珍稀食药用菌，类胡萝卜素不仅为其重要活性成分，而且影响子实体的外观品相，但是类胡萝卜素产生的影响因素不明。【目的】揭示氮源对蛹虫草生长和类胡萝卜素产生的影响。【方法】测定不同氮源培养基中菌株生长速度、分生孢子产生及类胡萝卜含量，筛选菌株生长的最适氮源，进一步研究不同浓度的氮源对蛹虫草生长及类胡萝卜素产生的影响，并测定不同光照条件下氮源浓度对蛹虫草子实体类胡萝卜素产生的影响。【结果】蛹虫草在不同的氮源培养基中菌落形态和类胡萝卜素产生存在明显差异。麦麸和黄豆粉培养基中菌株生长速度最快，但是菌落稀疏，正面分别呈现荧光黄色和极微弱红色；蛋白胨和酵母提取物培养基中菌落致密，产孢量极显著高于其它氮源培养基(P<0.01)，菌落正面为橙黄色；甘氨酸和柠檬酸为氮源时完全没有色素产生，其它无机和氨基酸氮源培养基平板背面有微量色素产生。固体和液体静置培养条件下均发现蛋白胨浓度在0?3%的范围内，随着浓度的增加，类胡萝卜素含量增加；子实体栽培中不同的氮源浓度均表现为蓝光光照条件下类胡萝卜素含量显著高于白光；而在白光和蓝光光照条件下均表现为蛋白胨浓度为1%时类胡萝卜素含量最高，分别为2 809.38±386.24 μg/g和4 093.75±518.37 μg/g。【结论】氮源种类和浓度显著影响蛹虫草类胡萝卜素的产生，蓝光光照和1%蛋白胨浓度为子实体类胡萝卜素产生的最佳条件，这为栽培富含类胡萝卜素的蛹虫草子实体提供了试验依据。

Abstract:

[Background] Cordyceps militaris is one of the famous medicinal fungi. Carotenoid is not only an important active component but also affects the appearance of fruiting body. However, the factors regulating its production are unknown. [Objective] To reveal the effects of nitrogen sources on the growth and carotenoid production of C. militaris. [Methods] The growth rate, conidia and carotenoid production on media with different nitrogen sources were determined and the optimum nitrogen sources were selected. The effects of nitrogen concentration on carotenoid production of C. militaris fruiting body under different light conditions were further determined. [Results] There were significant differences in growth and carotenoid production of C. militaris on media with different nitrogen sources. The growth rate was the fastest in wheat bran and soybean powder media, showing as fluorescent yellow and very weak red, respectively. The conidia produced in peptone and yeast extract media were significantly more than that in other nitrogen sources (P<0.01), and the colony was orange. There was no pigment production in inorganic nitrogen source media except for trace pigments on the back of plate of glutamic acid and ammonium chloride. It was found that the carotenoid content increased with the increase of peptone concentration in the range of 0?3%. Blue light was more suitable for the carotenoid production in fruiting body than white light. The carotenoid contents were the highest with the peptone concentration of 1% under both white and blue light conditions, 2 809.38±386.24 μg/g and 4 093.75±518.37 μg/g respectively. [Conclusion] Nitrogen source and its concentration significantly affected the carotenoid production in C. militaris. Blue light and peptone concentration of 1% were the best conditions for carotenoid production in fruiting bodies. This study will be helpful for cultivating C. militaris fruiting body rich in carotenoid.