高山被孢霉发酵生产花生四烯酸的宏观形态

采用图像处理技术对高山被孢霉(Mortierella alpina)发酵过程中的不同形态进行分析,并对其产花生四烯酸(ARA)能力进行了比较。研究发现:复合N源中蛋白胨与酵母粉比例是影响高山被孢霉宏观形态的重要因素,球形形态生长的菌体中ARA产量较分散,菌丝体中ARA产量高;在球形形态中,空心球的菌体生物量低,ARA比例低,蓬松球可以兼顾菌体高生物量、高油脂比例及高ARA比例。产ARA能力由生物量、油脂比例及油脂中ARA比例共同决定。结果表明:直径大约4 mm、成核区域面积大约为43.6%、紧密度为71.36的蓬松球形态,是高山被孢霉一种相对较佳的发酵形态,其菌体产ARA能力分别是空心球和分散丝状菌体产ARA能力的2.01和2.70倍。

Macro-morphology characterization of Mortierella alpina during the cultivation

An image processing technology was employed to analyze the different morphology features of Mortierella alpina,then their arachidonic acid（ARA） production capacities were compared.The results showed that the mixing ratio of peptone to yeast extract in the complex nitrogen source was important factors to affect the macroscopic morphology,the ARA production of mycelia grown in the form of pellet was the higher than that in dispersed mycelia.Among different pellet forms,the lipid content in the hollow pellet was highest while the biomass, and ARA content were the highest in the fluffy pellets.The ARA production capacity was determined by the biomass, lipid content in biomass, and the ARA content in lipid.Based on these factors,the ARA production capacity of fluffy pellets was 2.01,2.70 fold compared with that of hollow pellets and dispersed filaments, respectively.Therefore, the fluffy pellets were the optimum morphology for M.alpina to produce ARA in batch cultivation, whose morphological characteristics were as follows：the mean diameter 4 mm,the area pellet core 43.6%of total mycelia area, the compactness 71.36.