Comparative analysis of nonvolatile and volatile metabolites in <i>Lichtheimia ramosa</i> cultivated in different growth media

<i>Lichtheimia ramosa</i> is one of the predominant filamentous fungi in Korean traditional <i>nuruk</i>. The nonvolatile and volatile metabolites of <i>L. ramosa</i> cultivated in three growth media: complete medium (CM), potato dextrose broth (PDB), and sabouraud dextrose broth (SDB), were investigated and compared. Among nonvolatile metabolites, serine, lysine, and ornithine increased in CM and PDB cultivated with <i>L. ramosa</i> during the exponential phase. In addition, glucose level increased in CM whereas decreased in PDB and SDB. The major volatile metabolites in the extract samples were acetic acid, ethanol, 3-methyl-2-buten-1-ol, 2-phenylethanol, ethylacetate, 2-furaldehyde, 5-(hydroxymethyl)-2-furaldehyde, 2,3-dihydro-3,5,-dihydroxy-6-methyl-4<i>H</i>-pyran-4-one, and <i>α</i>-humulene. In particular, the levels of volatile metabolites related to <i>makgeolli</i> (e.g., acetic acid, ethanol, and ethyl acetate) were highest in extracts cultivated in CM. On the other hand, the level of 2-phenylethanol was relatively higher in PDB and SDB, possibly due to there being more phenylalanine present in the biomass sample in media.枝状小克银汉霉（Lichtheimia ramosa）是韩国传统酒曲（nuruk）中主要的丝状真菌之一。本研究对分别在三种培养基——完全培养基（complete medium, CM）、马铃薯葡萄糖肉汤（potato dextrose broth, PDB）以及沙氏葡萄糖肉汤（sabouraud dextrose broth, SDB）——中培养的<i>L. ramosa</i>的非挥发性代谢物与挥发性代谢物进行了分析与比较。在非挥发性代谢物中，处于指数生长期的该菌株在CM与PDB培养基中，其丝氨酸、赖氨酸与鸟氨酸的含量均有所升高。此外，CM培养基中的葡萄糖含量出现上升，而PDB与SDB培养基中的葡萄糖含量则有所下降。提取物样品中的主要挥发性代谢物包括乙酸、乙醇、3-甲基-2-丁烯-1-醇、2-苯乙醇、乙酸乙酯、2-糠醛、5-羟甲基-2-糠醛、2,3-二氢-3,5-二羟基-6-甲基-4<i>H</i>-吡喃-4-酮以及<i>α</i>-葎草烯。尤为值得注意的是，与韩国浊酒（makgeolli）相关的挥发性代谢物（如乙酸、乙醇与乙酸乙酯）在CM培养基培养的提取物中含量最高。与之相对，2-苯乙醇在PDB与SDB培养基培养的样品中含量相对更高，这可能是由于对应培养基的菌体样本中含有更多的苯丙氨酸所致。