Alcaligenes sp. YBY降解吲哚的特性研究

Characterization of an Indole-degrading Bacterium Alcaligenes sp. YBY

该研究从近海泥沙样品中,分离纯化得到1株能以吲哚为唯一碳源生长的菌株,经16S rRNA基因序列分析鉴定为产碱杆菌(Alcaligenes),命名为YBY。考察影响菌株生长和降解吲哚的环境因素,并对菌株降解吲哚的机理进行推测。结果表明,菌株YBY生长和降解吲哚的最佳条件为pH 6.77,转速150 r/min。菌株具有较好的底物广谱性,能以柠檬酸钠、2-吲哚酮、苯酚、苯甲酸、邻氨基苯甲酸等物质为唯一碳源生长。利用液相色谱、飞行时间、质谱联用对菌株代谢吲哚的产物进行分析,发现中间产物主要为靛红、靛蓝和龙胆酸,由此推测的代谢途径为:吲哚首先被羟化成吲哚酚,吲哚酚二聚成靛蓝或者氧化成靛红,靛红进一步转化成龙胆酸。

A bacterial strain named YBY, which could use indole as the sole carbon source for growth, was obtained from the offshore sediment samples. Based on 16 S rRNA gene sequence analysis, the strain was identified as Alcaligenes sp.The environmental factors of strain growth and indole degradation were investigated, and the pathway of indole metabolism was proposed in the present study. Results showed that pH 6.77 and rotate speed of 150 r/min were more suitable for the growth and indole degradation of strain YBY. The strain YBY occupied a broad substrate spectrum, which could use sodium citrate, 2-indole ketone, phenol, benzoic acid and anthranilic acid as the sole carbon source for growth. The liquid chromatography/time-of-flight/mass spectrometry(LC/TOF/MS) was used to analyze the intermediates of indole degradation, and isatin, indigo, gentistic acid were identified in the indole degradation process. It could be proposed that the first step of indole degradation was hydroxylation of indole to indoxyl. Indoxyl was dimerization to indigo or oxidized to isatin, and iatain was further transformed into gentistic acid.