红色红曲菌M7液态发酵菌丝体形态对红曲色素产量的影响

Influence of Mycelium Morphology on the Yield of Monascus Pigments During Submerged Fermentation of Monascus Ruber M7

丝状真菌液态发酵过程中,菌丝体形态特征对其生理状态以及代谢产物合成有重要影响。为了研究红曲菌菌丝体形态与红曲色素生产能力之间的关系,利用微粒强化培养(Microparticle-enhanced cultivation,MPEC)技术,调节菌丝体以不同形态生长,并比较其发酵过程中的相关参数差异。结果发现,在马铃薯葡萄糖液体培养基(Potato dextrose broth,PDB)中添加大米粉颗粒,红色红曲菌M7的菌丝体形态发生了显著变化,当添加量为0、0.10%和0.20%时,分别形成典型的团块状、球状和絮状菌丝体;球状和絮状菌丝体的碳源消耗速度加快、生物量增加、生长周期缩短、红曲色素产量提高;其中,絮状菌丝体的红曲色素生产能力最强,在发酵的6 d,其红色素、橙色素和黄色素产量达到最大值,分别为(26.7±2.1)U/mL、(41.9±3.1)U/mL和(34.6±2.6)U/mL,是球状菌丝体的2.0~2.1倍,团块状菌丝体的3.3~3.6倍。该结果表明,絮状菌丝体能显著提高红曲色素的产量,为液态发酵生产红曲色素的最佳菌丝体形态。

During the submerged fermentation of filamentous fungi,the mycelium morphology plays an important role in fungal physiology and metabolites biosynthesis.In order to understand the relationship between mycelium morphology and pigments productivity of Monascus ruber,a microparticle-enhanced cultivation(MPEC)method was employed to control the mycelium morphology,and the differences in the fermentation process were investigated.It was found that when particles of rice powder were added to potato dextrose broth(PDB),the mycelium morphology of M.ruber M7 was changed significantly.At the concentration of 0,0.10%and 0.20%,M.ruber M7 formed three typical mycelium morphologies:clump aggregations,spherical pellets and dispersed mycelium,respectively.When spherical pellets and dispersed mycelium formed,M.ruber M7 exhibited faster consumption of carbon source,higher biomass,shorter growth period and enhanced yield of Monascus pigments.The production of Monascus pigments by dispersed mycelium was found to be the highest,and on the 6th day of fermentation,the red,orange and yellow Monascus pigments were(26.7±2.1)U/mL,(41.9±3.1)U/mL and(34.6±2.6)U/mL,respectively,which were 2.0 to 2.1-folds as high as that of spherical pellets,and 3.3 to 3.6-folds as high as that of clump aggregations.These results suggested that dispersed mycelium promoted the production of Monascus pigments significantly,and was best morphological state for Monascus pigments production.