Growth rate and medium composition strongly affect folate content in Saccharomyces cerevisiae
Growth rate and medium composition strongly affect folate content in Saccharomyces cerevisiae
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DOI：
10.1016/j.ijfoodmicro.2007.12.004
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发表时间：
2008-03-31
影响因子：
5.4
通讯作者：
Andlid, Thornas
中科院分区：
文献类型：
--
作者：
Hjortmo, Sofia;Patring, Johan;Andlid, Thornas
在合成生长培养基、酵母蛋白胨葡萄糖培养基和糖蜜基培养基中进行有氧分批发酵期间，监测酿酒酵母菌株中的叶酸含量。在合成培养基中生长期间，在不同阶段观察到细胞内叶酸含量的大差异。特定的叶酸水平，表示每单位生物量，是最高的呼吸发酵生长（120微克/克），并在呼吸和静止期下降。因此，细胞的生理状态明显影响叶酸含量。这在恒化器培养物中得到证实，其中总细胞内叶酸含量随着生长速率的增加而线性增加（r（2）= 0.998），表明高生长速率，即呼吸发酵生长最有利于获得高比叶酸含量。然而，在复合培养基中，在整个分批生长过程中发现叶酸含量低得多（15-40 μ g/g）。仅检测到微小的生长期相关差异。这显示了培养基对酵母中叶酸含量的影响。为了进一步研究影响叶酸含量的组分，在添加特定组分的合成培养基中进行分批实验。添加肽和氨基酸的原始混合物（蛋白胨）广泛降低叶酸水平（90%），而逐个添加氨基酸对细胞内叶酸含量的影响很小。此外，补充合成培养基与pABA，叶酸或核苷酸没有改变细胞内叶酸含量。这项工作构成了为强化目的生产天然叶酸的优化过程的第一步，以及努力获得与环境条件有关的酵母中叶酸需求的基本理解。(C)2007 Elsevier B. V.保留所有权利。
Folate content in a Saccharomyces cerevisiae strain was monitored during aerobic batch fermentation in synthetic growth medium, yeast peptone dextrose medium, and a molasses based medium. During growth in the synthetic medium large differences in intracellular folate content was observed at different phases. Specific folate levels, expressed per unit biomass, were highest during respiro-fermentative growth (120 mu g/g) and decreased during the respiratory and stationary phases. Thus, the physiological state of the cells clearly affects the folate content. This was confirmed in chemostat Cultures where total intracellular folate content increased linearly with increasing growth rate (r(2) = 0.998), indicating high growth rate i.e. respiro-fermentative growth to be most favourable to obtain high specific folate content. In complex media however, much lower folate content (15-40 mu g/g) was found throughout the batch growth. Only minor growth-phase related differences were detected. This shows the impact of cultivation medium on folate content in yeast. To further investigate which components that influence folate content, batch experiments in synthetic medium with addition of specific components were performed. Adding a raw mixture of peptides and amino acids (peptone) decreased folate levels extensively (90%) whereas adding amino acids one-by-one only had minor effects on the intracellular folate content. Furthermore, supplementing synthetic medium with pABA, folate or nucleotides did not change the intracellular folate content. This work constitutes the first steps towards an optimised process for production of natural folates for fortification Purposes, as well as an effort to gain fundamental understanding of folate requirements in yeast in relation to environmental conditions. (C) 2007 Elsevier B.V. All rights reserved.