Metabolism of L-methionine linked to the biosynthesis of volatile organic sulfur-containing compounds during the submerged fermentation of Tuber melanosporum
Metabolism of L-methionine linked to the biosynthesis of volatile organic sulfur-containing compounds during the submerged fermentation of Tuber melanosporum
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黑孢块菌深层发酵过程中 L-蛋氨酸的代谢与挥发性有机含硫化合物的生物合成有关
DOI：
10.1007/s00253-013-5224-z
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发表时间：
2013-12-01
影响因子：
5
通讯作者：
Tang, Ya-Jie
中科院分区：
文献类型：
--
作者：
Liu, Rui-Sang;Zhou, Huan;Tang, Ya-Jie
块茎黑孢子菌被誉为烹饪中的黑钻石，因其独特的香气而备受推崇，这主要是由于其挥发性有机含硫化合物(VOSCs)。在发酵液中添加5g/L L蛋氨酸，转氨酶和α-酮酸脱羧酶活性分别提高103%和250%，而乙醇脱氢酶和去甲硫醇酶活性分别降低277%和39%。在此基础上，首次在黑孢霉液体发酵过程中检测到甲硫醇(MTL)、二甲基硫(DMS)、二甲基二硫化物(DMDS)、二甲基三硫醚(DMTS)、3-甲硫基丙醛(甲硫醇)和3-甲硫基-1-丙醇(甲硫醇)6种挥发性有机化合物。这些结果表明，VOSCs的生物合成是由转氨酶和α-酮酸脱羧酶触发的。培养第4天前，随着L蛋氨酸浓度(5、10、15和20g/L)的增加，甲硫醇和甲硫醇的产量增加，且甲硫醇是埃利希途径的主要产物。MTL的产生在第4天后显著减少，DMDS显著增加，DMDS是去甲硫醇途径的主要产物。与总硫通量为11.33~24.32µM的脱硫醇途径相比，总硫通量为6,149~10,330µM的Ehrlich途径是VOSCs生物合成的主要途径。这是首次将L蛋氨酸的代谢与黑霉菌深层发酵过程中的埃利希途径和去甲硫化途径合成VOSCs联系起来。
Tuber melanosporum, known as the black diamond of cuisine, is highly appreciated for its unique and characteristic aroma, which is mainly due to its volatile organic sulfur-containing compounds (VOSCs). In this work, by adding 5 g/L l-methionine to the fermentation medium, the activities of aminotransferase and alpha-ketoacid decarboxylase were significantly enhanced by 103 and 250 %, respectively, while the activities of alcohol dehydrogenase and demethiolase were decreased by 277 and 39 %. Then, the six VOSCs, i.e., methanethiol (MTL), dimethyl sulfide (DMS), dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), 3-(methylthio)propanal (methional), and 3-(methylthio)-1-propanol (methionol), were first detected in the submerged fermentation of T. melanosporum. These results indicated that the biosynthesis of VOSCs was triggered by aminotransferase and alpha-ketoacid decarboxylase. The production of methional and methionol increased with the increased concentrations of l-methionine (i.e., 5, 10, 15, and 20 g/L) before day 4 of the culture protocol, and methionol was the major product in the Ehrlich pathway. The production of MTL was significantly decreased after day 4 with a significantly increased DMDS, and DMDS was the major product of the demethiolation pathway. Compared with the demethiolation pathway with a total flux of sulfur of 11.33-24.32 mu M, the Ehrlich pathway with a total flux of sulfur of 6,149-10,330 mu M was considered the major pathway for the biosynthesis of VOSCs. This is the first report linking the metabolism of l-methionine to the biosynthesis of VOSCs by the Ehrlich and demethiolation pathways during the submerged fermentation of T. melanosporum.