Metabolism and synthesis of lipids in the polyunsaturated fatty acid-producing fungus Mortierella alliacea.
Metabolism and synthesis of lipids in the polyunsaturated fatty acid-producing fungus Mortierella alliacea.
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DOI：
10.5650/jos.60.11
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发表时间：
2011
影响因子：
1.5
通讯作者：
Worapol Jermsuntiea;T. Aki;S. Kawamoto;K. Ono
中科院分区：
文献类型：
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作者：
Worapol Jermsuntiea;T. Aki;S. Kawamoto;K. Ono
葱白被孢霉（Mortierella alliacea）YN-15是多不饱和脂肪酸（PUFA），特别是花生四烯酸的有前途的工业生产者。为了更有效地生产PUFAs，研究了外部供应的植物油，富含α-亚麻酸（ALA）的亚麻籽三酰甘油（TAG）的代谢，并追踪其脂质和脂肪酸代谢产物组成的时间依赖性变化。添加亚麻籽TAG到生长的培养物中导致菌丝体中细胞外1，2-二酰基甘油（DAG）的瞬时增加，并且1，3-DAG甚至更多。随后是两种DAG的减少和TAG的增加。二十碳五烯酸（EPA），一个去饱和和延长产品的ALA，积累到更大程度上在细胞磷脂比中性脂质。此外，将游离脂肪酸形式的ALA添加到培养物中导致EPA的产生。然而，EPA的生产没有观察到添加ALA丰富的1，2-或1，3-DAG，表明从外源脂质释放的脂肪酸用于菌丝体TAG的再合成。这些结果表明，TAG可能是由胞外脂肪酶水解，而其合成可能是由胞内酶催化。适当调节这些酶可能是一种有效的策略，以提高PUFA生产植物油补充。
The fungal strain Mortierella alliacea YN-15 is a promising industrial producer of polyunsaturated fatty acids (PUFAs), in particular arachidonic acid. In order to more efficiently produce PUFAs, the metabolism of an externally supplied plant oil, α-linolenic acid (ALA)-rich linseed triacylglycerol (TAG), was examined, and time-dependent changes in the composition of its lipid and fatty acid metabolites were traced. Addition of linseed TAG to growing cultures resulted in a transient increase in extracellular 1,2-diacylglycerol (DAG), and even more so of 1,3-DAG, in the mycelia. This was followed by a decrease in both DAGs and an increase in TAG. Eicosapentaenoic acid (EPA), a desaturated and elongated product of ALA, accumulated to a greater extent in cellular phospholipids than in neutral lipids. Moreover, the addition of ALA in free fatty acid form to the culture led to the generation of EPA. However, EPA production was not observed upon addition of ALA-rich 1,2- or 1,3-DAG, indicating that fatty acids released from exogenous lipids were used for resynthesis of mycelial TAG. These results suggested that TAG might be hydrolyzed by extracellular lipases, whereas its synthesis might be catalyzed by intracellular enzymes. Appropriate regulation of such enzymes might be an effective strategy to enhance PUFA production under plant oil supplementation.