渗透压对黑曲霉菌丝形态和葡萄糖氧化酶活力的影响

Effect of osmotic pressure on filament morphology and glucose oxidase activity of Aspergillus niger

发酵培养基渗透压对黑曲霉菌丝生长形态和葡萄糖氧化酶活力产生巨大的影响。平板培养的图像表明,随着渗透压的增长,菌丝体形态呈现出了从菌丝缠绕的颗粒球状向发散菌丝团状的转变。通过吖啶橙荧光染色和光学显微镜观察的结果,确定了核糖核酸丰富的蛋白活性区域分布在丝状形态中和颗粒球团的外层上。对比了底物中添加葡萄糖、果糖、蔗糖、甘油、聚乙二醇和氯化钠所产生的渗透压对葡萄糖氧化酶活力的影响。在200 g/L葡萄糖培养基中产生的渗透压为900.71 mOsmol/(kg·H_(2)O),可以获得最高的葡萄糖氧化酶活力(11.23 U/mL)。渗透压影响的评估结果,为黑曲霉产葡萄糖氧化酶发酵工艺的优化提供了理论依据。

The osmotic pressure of the substrate could greatly influence the morphology of Aspergillus niger and glucose oxidase activity. Based on the plate cultivation, the mycelial morphology varied from the wound pellet to diverge mycelium mass, with the increases of osmotic pressure in medium. Besides, the optical microscopy images confirmed that the abundant protein activity regions were distributed in the filamentous morphology and the outer layer of the pellet. Furthermore, the effects of osmotic pressure on the glucose oxidase activity of A. niger by adding glucose, fructose, sucrose, glycerol, polyethylene glycol(PEG) and NaCl in the substrate were compared. Results indicated the highest glucose oxidase activity of 11.23 U/mL can be obtained when using 200 g/L glucose containing medium(with osmotic pressure of 900.71 mOsmol/kg·H_(2)O) as substrate. Therefore, the evaluation of osmotic pressure provided a theoretical basis for the highly activated glucose oxidase production by A. niger.