Aerobic and anaerobic degradation pathways for N-heterocyclic aromatic compound indole

Abstract

Both aerobic and anaerobic enrichment cultures were obtained from mangrove sediment using indole as the sole source of carbon and energy. Biochemical pathway of degradation was elucidated after identification of the degradation intermediates. Results showed that hydroxylation at 2 and 3 positions of the pyrrole ring is the initial step, resulting oxindole and isatin, respectively, regardless of the experimental conditions including aerobic and strictly anaerobic conditions (methanogenic and sulfate-reducing). Substitution of methyl group at 1,2 and 3 position on 1-methylindole, 2-methylindole and 3-methylindole inhibits initial microbial attack significantly. It is apparent that a common degradation pathway exists for N-heterocyclic aromatic compounds and the degradability is determined by the substitution groups and position.

用紅樹林的底泥通過富集培養得到在好氧或厭氧條件下能完全礦化吲哚的細菌 ,并對降解過程及中間代謝產物進行了鑒定。此研究中 ,吲哚化合物是培養液中的唯一碳和能量來源 ,而厭氧條件包括有產甲烷和硫酸鹽還原。結果表明 ,不論在哪種條件下 ,吲哚降解過程分二步羰基化反應 ,分別發生在 2和 3位上 ,形成氧化吲哚和靛紅。同時 ,1、2或 3位上的甲基替代使 1 甲基吲哚 ,2 甲基吲哚和 3 甲基吲哚的降解受到嚴重抑制。顯然 ,雜環類芳香族化合物的代謝有其共同點 ,同時不同替代會完全改變有機物的可降解程度