Changes in alginate molecular mass distributions, broth viscosity and morphology of Azotobacter vinelandii cultured in shake flasks
Changes in alginate molecular mass distributions, broth viscosity and morphology of Azotobacter vinelandii cultured in shake flasks
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摇瓶培养的维氏固氮菌海藻酸盐分子量分布、肉汤粘度和形态的变化
DOI：
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发表时间：
1997
影响因子：
5
通讯作者：
E. Galindo
中科院分区：
文献类型：
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作者：
C. Peña;N. Campos;E. Galindo
摘要在摇瓶中研究了不同曝气条件对黄氏固氮菌海藻酸盐产量和分子量的影响。在挡板烧瓶中，细菌生长速度更快，产生的海藻酸盐（1.5 g/l）少于传统（未挡板烧瓶）（4.5 g/l）。培养液的粘度也受烧瓶类型的影响。与挡板烧瓶（30 cP）相比，无挡板烧瓶获得了更高的最终粘度[520 cP (520 mPa s)]。后一种现象与分子质量分布的变化密切相关。在这两种情况下，平均分子质量随培养年龄的增加而增加；然而，在发酵结束时，在未挡板烧瓶中获得的海藻酸盐的平均分子质量比在挡板烧瓶中获得的高5倍。随着培养的进行，在无挡板烧瓶中培养的固氮菌细胞直径增加，而在挡板烧瓶中培养的固氮菌细胞尺寸减小。
Abstract The effect of different aeration conditions during the culture of Azotobacter vinelandii on the production and molecular mass of alginate was evaluated in shake flasks. In baffled flasks, the bacteria grew faster and produced less alginate (1.5 g/l) than in conventional (unbaffled) flasks (4.5 g/l). The viscosity of the culture broth was also influenced by the type of flask. Higher final viscosities were attained in unbaffled flasks [520 cP (520 mPa s)] as compared to baffled flasks (30 cP). This latter phenomenon was closely related to the changes in the molecular mass distribution. In either cases, the mean molecular mass increased with culture age; however, at the end of the fermentation, the mean molecular mass of the alginate obtained in unbaffled flasks was fivefold higher than that obtained in baffled flasks. As the culture proceeded, the cells of Azotobacter grown in unbaffled flasks increased in diameter, whereas those cultured in baffled flasks decreased in size.