5种金属离子对紫色红曲霉主要次生代谢物谱的调节作用

黄胜男; 高梦祥; 刘应保

doi:10.13386/j.issn1002-0306.2020080154

5种金属离子对紫色红曲霉主要次生代谢物谱的调节作用

Regulatory Effect of 5 Metal Ions on the Spectrum of Major Secondary Metabolites of Monascus purpureus

摘要

摘要: 目的：研究金属离子对紫色红曲霉生长和主要次生代谢物合成的调节作用。方法：将紫色红曲霉孢子接种到含不同浓度的金属离子（Cu²⁺、Zn²⁺、Mg²⁺、Mn²⁺、Co²⁺）的固体培养基，观察不同离子对其生长和色素合成的影响；同时，将不同浓度的上述离子及金属螯合剂8-羟基喹啉分别接种到液体培养基中，测定紫色红曲霉生物量、红曲色素、莫纳克林K、γ-氨基丁酸和桔霉素等主要次生代谢物含量及发酵液中代谢物谱变化。结果：Cu²⁺（0.5 mmol/L）处理导致水溶红、橙、黄色素产量分别提升了2.01、2.07和1.73倍；醇溶色素分别增加了2.83、1.74和1.95倍；莫纳克林K和桔霉素分别增加了1.78和5.53倍。Zn²⁺（0.5 mmol/L）促使水溶、醇溶色素分别增加了93.3%、78.6%、57.6%和2.9、1.54、0.54倍。莫纳克林K和桔霉素则分别增加了0.92和6.91倍。0.5 mmol/L的Mg²⁺处理导致生物量有所下降，但无显著差异；水溶、醇溶色素则分别增加了2.68、2.25、2.02倍和1.26、1.23、1.82倍；莫纳克林K则增加了51.8%。0.25 mmol/L的Mg²⁺则使桔霉素提升了1.79倍。Mn²⁺（0.5 mmol/L）刺激水溶、醇溶色素产量分别增加了48.3%、29.9%、24.8%和131.1%、83.6%、49.2%，莫纳克林K增加了1.01倍。而桔霉素则在1 mmol/L Mn²⁺刺激下增加了92.3%。Co²⁺（0.5、1 mmol/L）导致生物量分别降低了47.9%和53.7%，而醇溶色素则分别提高了4.07、5.04、2.62倍和3.07、3.41、2.70倍，对莫纳克林K合成无作用；桔霉素产量分别降低了90.8%和93.9%。上述离子均不利于γ-氨基丁酸的合成。金属离子螯合剂8-羟基喹啉（20 μmol/L）使红曲霉生物量降低了26.9%，水溶色素分别下降了40.6%、34.3%和26%。莫纳克林K和桔霉素分别降低了56.7%和90.1%。发酵液的波谱（200~600 nm）扫描结果发现，金属离子仅调节代谢物的产量，并不改变紫色红曲霉代谢物种类。结论：金属离子不仅影响紫色红曲霉的生长，并显著调节其主要次生代谢物谱。

Abstract: Objective: This study was to investigate the regulatory effect of Cu²⁺, Zn²⁺, Mg²⁺, Mn²⁺ and Co²⁺ on the growth and the major secondary metabolite of M. purpureus. Methods: The spores of M. purpureus were inoculated into solid medium with different concentration of metal ions, and investigate the effects of different ions on their growth and pigments synthesis. Meanwhile, different concentrations of metal ions and 8-hydroxyquinoline were added into the liquid medium respectively, and biomass, the main secondary products such as Monascus pigment, monacolin K, γ-aminobutyric acid, citrinin and changes in the metabolite profile in the fermentation broth were measured. Results: The result showed that Cu²⁺ (0.5 mmol/L) leads to a 1.01, 1.07 and 0.73 times increase in the yield of water-soluble red, orange and yellow pigments, respectively, and alcohol-soluble pigments increased by 2.83, 1.74 and 1.95 times, respectively. Monacolin K and citrinin increased by 1.78 and 5.53 times, respectively. The water-soluble and alcohol-soluble pigments under Zn²⁺ (0.5 mmol/L) increased by 93.3%, 78.6%, 57.6%, and 2.9, 1.54, and 0.54 times, respectively, monacolin K and citrinin increased by 0.92 and 6.91 times, respectively. Biomass was no changed under Mg²⁺(0.5 mmol/L) treatment, but the water-soluble and alcohol-soluble pigments were increased by 2.68, 2.25, 2.02-fold and 1.26, 1.23 and 1.82-fold, respectively, monacolin K increased by 51.8%. Whereas, citrinin increased by 1.79 times at the concentration of 0.25 mmol/L Mg²⁺. Mn²⁺ (0.5 mmol/L) led to increase of the yields of water-soluble and alcohol-soluble pigments by 48.3%, 29.9%, 24.8% and 131.1%, 83.6% and 49.2%, respectively, and monacolin K increased by 1.01-fold. Citrinin increased by 92.3% under the stimulation of 1 mmol/L Mn²⁺. Co²⁺ (0.5, 1 mmol/L) led to a 47.9% and 53.7% reduction of biomass, respectively. The alcohol-soluble pigments was improved by 4.07, 5.04, 2.62 times, and 3.07, 3.41, 2.70 times, respectively, citrinin decreased by 90.8% and 93.9%, respectively, with no effect on the Monacolin K synthesis. None of the above ions were detrimental to the synthesis of γ-aminobutyric acid. The metal ion chelator 8-hydroxyquinoline(20 μmol/L) was responsible for a 26.9% decrease in biomass and a 40.6%, 34.3% and 26% decrease in water-soluble pigments, respectively, and monacolin K and citrinin decreased by 56.7% and 90.1%, respectively. The spectrum (200~600 nm) scanning of fermentation broth showed that the metal ions did not change the metabolite types, but only regulated the metabolite content. Conclusion: The results suggested that metal ions not only affect the growth of M. purpureus, but also significantly regulate its main secondary metabolite profile.