【作者】 王兰；

【导师】 周立平；

【作者基本信息】 浙江工业大学 ， 发酵工程， 2008， 硕士

【摘要】 就收集的红曲菌株进行筛选,得到一株Monacolin K产量相对最高的红色红曲NMonascus ruber GM011,其产量为258.2mg/L。以此菌株为原始出发菌株,孢子通过紫外、LiCl、紫外-LiCl复合诱变、亚硝酸处理和硫酸二乙酯诱变,得到桔霉素含量较小的Monacolin K产量较高的突变株W₂₈₃,其Monacolin K产量为395.3mg/L,较出发菌株提高了53.1%,传代性实验表明该菌株产量较稳定。实验发现适量添加乙酸可明显促进红曲发酵液中Monacolin K的产量。未添加乙酸的发酵液中Monacolin K含量为390.3mg/L,添加乙酸后发酵液中Monacolin K含量提高到971.8 mg/L,提高了149.0%;而随着乙酸添加量的进一步增加,红曲产Monacolin K的能力反而有所下降;乙酸乙酯、乙醇及正己烷也会影响红曲产Monacolin K的能力;培养基中适量添加MgSO₄、ZnSO₄对红曲产Monacolin K有一定的促进作用,但随着添加量的进一步增加,反而抑制了红曲产Monacolin K的能力,尤其是ZnSO₄,当添加量达到4g/L时,发酵液中菌丝体的生长明显减弱;外界环境中较高的渗透压,可能会刺激红曲细胞合成大量的Monacolin K来应对这种高渗环境。添加某些具有降血糖功效的常见食品于红曲液体培养基中,发现培养基中添加薏米仁,可明显促进红曲产Monacolin K的能力,产量可达917.7 mg/L,增加了135.61%。通过单因素实验,Plackett-Burman设计以及响应面法,得到W₂₈₃产Monacolin K的最优发酵条件（g/L）:葡萄糖20,蛋白胨16.3,甘油95.7,MgSO₄ 1,NaNO₃ 6.8,ZnSO₄ 2,KH₂PO₄ 1,薏米仁2.5,KNO₃5,pH4.4,接种量8%。按照此发酵条件培养,Monacolin K产量可达到1290mg/L,是未优化前的3.3倍,出发菌株的5倍。更多还原

【Abstract】 The collected Monascus ssp.were screened,a strain named Monascus ruber GM011 with high productivity of Monacolin K was obtained,whose yield reached to 258.2mg/L.It was used as the original strain,whose spores were treated with ultraviolet,LiCl,ultraviolet-LiCl,HNO₂ and DES.A mutant strain named W₂₈₃was gained,whose yield of Monacolin K increased 53.1%in comparison with the original strain,reached to 395.3mg/L.The production of Monacolin K was stabilized in genetics.Acetic acid,ethyl acetate,ethanol and n-hexane were added in the process of liquid fermentation.The results showed that acetic acid could promote the productivity of Monacolin K by Monascus.The production of Monacolin K was 971.8 mg/L while it was 390.3 mg/L without adding acetic acid,which increased by 149%.It was reduced if it was added more acetic acid in the culture medium.Ethyl acetate,ethanol and n-hexane could affect the productivity of Monacolin K also.Through the productivity of Monacolin K could be promoted by adding a little of MgSO₄、ZnSO₄ in the culture medium,it would be inhibited too more. When ZnSO₄ was 4g/L in the culture medium,W₂₈₃grew abnormally.The high osmotic stress probablely leaded to higher production of Monacolin K.The productivity of Monacolin K could be promoted by adding Job’s-tears,and the production could reach to 917.7 mg/L.Response Surface Methodology was applied to optimize the culture conditions for the production of Monacolin K produced by W₂₈₃.In the first optimization step,a Plackett-Burman design was used to evaluate the influence of related factors.Peptone,glycerin and NaNO₃ influenced the production of Monacolin K observably.The maximal production 1290mg/L was obtained under the following conditions（g/L）:glucose 20, peptone 16.3,glycerin 95.7,MgSO₄ 1,NaNO₃ 6.8,ZnSO₄ 2,KH₂PO₄ 1, Job’s-tears 2.5,KNO₃ 5,initial pH 4.4,8%inoculum.The optimized culture conditions resulted in a 230%increase of the production of Monacolin K,as compared with the original conditions,which was five times as more as the parent strain.更多还原