Production of ergothioneine by Methylobacterium species.
Production of ergothioneine by Methylobacterium species.
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DOI：
10.3389/fmicb.2015.01185
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发表时间：
2015
影响因子：
5.2
通讯作者：
Tani A
中科院分区：
文献类型：
--
作者：
Alamgir KM;Masuda S;Fujitani Y;Fukuda F;Tani A
代谢组学分析表明，甲基杆菌细胞积累了大量的麦角硫因（EGT），这是一种含硫的，非蛋白质，抗氧化氨基酸来源于组氨酸。本文研究了植物表面共生甲基杆菌EGT的生物合成及其在甲基营养和生理中的作用。几乎所有的甲基杆菌型菌株都能合成EGT。我们选择了一个最高产的菌株（M。aquaticum菌株22 A），通过优化培养条件，研究了EGT发酵生产的可行性。甲醇作为碳源是最好的生产底物。在38天内，生产率达到1000 μg/100 ml培养物（1200 μg/g湿重细胞，6.3 mg/g干重）。接下来，我们鉴定了负责EGT合成的基因（egtBD），并产生了EGT生产缺陷的缺失突变体。与野生型相比，突变体在甲醇和植物表面上表现出更好的生长，以及对热处理和紫外线（UV）和阳光照射的严重敏感性。这些结果表明，EGT是不参与甲基营养，但在自然条件下，它们的叶球生活方式的适合度的属。
Metabolomic analysis revealed that Methylobacterium cells accumulate a large amount of ergothioneine (EGT), which is a sulfur-containing, non-proteinogenic, antioxidative amino acid derived from histidine. EGT biosynthesis and its role in methylotrophy and physiology for plant surface-symbiotic Methylobacterium species were investigated in this study. Almost all Methylobacterium type strains can synthesize EGT. We selected one of the most productive strains (M. aquaticum strain 22A isolated from a moss), and investigated the feasibility of fermentative EGT production through optimization of the culture condition. Methanol as a carbon source served as the best substrate for production. The productivity reached up to 1000 μg/100 ml culture (1200 μg/g wet weight cells, 6.3 mg/g dry weight) in 38 days. Next, we identified the genes (egtBD) responsible for EGT synthesis, and generated a deletion mutant defective in EGT production. Compared to the wild type, the mutant showed better growth on methanol and on the plant surface as well as severe susceptibility to heat treatment and irradiation of ultraviolet (UV) and sunlight. These results suggested that EGT is not involved in methylotrophy, but is involved in their phyllospheric lifestyle fitness of the genus in natural conditions.