Abstract: The optimization of medium components and culture conditions for improved spore production of Monascus purpureus M-4 in submerge culture was performed using a combination of one-factor-at-a-time (OFAT) method and response surface methodology (RSM). The OFAT results showed that potato extract powder and glucose were the optimal nitrogen and carbon source, respectively and that their optimal concentrations were 0.4 and 2.0 g/100 mL, respectively. The optimal culture conditions that provided the maximum number of spores were as follows: initial medium pH 6.72 (natural pH), medium volume in a 500-mL triangular flask 120 mL, concentration of added CaCO3 2.0 g/100 mL, number of passages 2, and culture time 72 h. Potato extract powder and glucose concentration as well as culture time were identified as main variables that influence spore production and their optimal levels were determined to be respectively 0.38 g/100 mL, 2.2 g/100 mL and 6.5 d using RSM. The highest spore number of (7.47 ± 0.15) × 106 CFU/mL was experimentally obtained under the optimized conditions, which was close to the predicted value (7.53 ± 0.31) × 106 CFU/mL. The average error between the predicted and experimental values was 0.79%. A 31.13-fold increase in spore number was achieved by the optimization. Besides, the spore-producing ability per unit volume of strain M-4 was greatly improved.

Key words: Monascus purpureus M-4; medium; fermentation conditions; spore number; optimization

摘要： 采用单因素试验和响应面方法对紫红曲霉M-4液态发酵产孢子的培养基成分和培养条件等因素进行优 化。结果表明：马铃薯浸粉为最佳氮源，其最适添加量为0.4 g/100 mL；葡萄糖为最佳碳源，其最适添加量为 2.0 g/100 mL；培养基最适pH值为自然条件下的pH值（6.72）；培养基最佳装液量为120 mL（500 mL锥形瓶）； 添加2.0 g/100 mL CaCO3的培养基中菌株发酵产孢子数提高较为明显；最佳传代次数为2 代，当菌株培养时间达到 72 h时，菌株产孢子数达到最大。进一步通过响应面方法分析得到影响紫红曲霉M-4液态发酵产孢子数3 个主要因 素的优化条件为马铃薯浸粉添加量0.38 g/100 mL、葡萄糖添加量2.2 g/100 mL、培养时间6.5 d，此条件下紫红曲霉 M-4最大产孢子数为（7.47±0.15）×106 CFU/mL，接近理论预测值（7.53±0.31）×106 CFU/mL，实验平均误差为 0.79%。优化后紫红曲霉M-4产孢子数较优化前提高30.13 倍，菌株单位体积产孢子能力得到大幅度提升。

关键词: 紫红曲霉M-4；培养基；发酵条件；产孢子数；优化