Relationship between structures of substituted indolic compounds and their degradation by marine anaerobic microorganisms

TY - JOUR

T1 - Relationship between structures of substituted indolic compounds and their degradation by marine anaerobic microorganisms

AU - Gu, Ji Dong

AU - Fan, Yanzhen

AU - Shi, Hanchang

N1 - Funding Information: This research was supported by the Visiting Scholar Foundation of Key Laboratory at Tsinghua University to Gu. Additional support was by the Chinese Academy of Sciences and the CRCG grant of The University of Hong Kong.

PY - 2002/9

Y1 - 2002/9

N2 - Degradation of selected indolic compounds including indole, 1-methylindole, 2-methylindole, and 3-methylindole was assessed under methanogenic and sulfate-reducing conditions using the serum-bottle anaerobic technique and marine sediment from Victoria Harbour, Hong Kong as an inoculum. Our results showed that indole degradation was achieved in 28 days by a methanogenic consortium and 35 days by a sulfate-reducing consortium. During degradation under both conditions, two intermediates were isolated, purified and identified as oxindole and isatin (indole-2,3-dione) suggesting that both methanogenic and sulfate-reducing bacteria use an identical degradation pathway. Degradation processes followed two steps of oxidation accomplished by hydroxylation and then dehydrogenation at 2- and then 3-position sequentially prior to the cleavage of the pyrrole ring between 2- and 3-positions. However, none of 1-methylindole or 2-methylindole was degraded under any conditions. 3-Methylindole (3-methyl-1H-indole, skatole) was transformed under methanogenic conditions and mineralized only under sulfate-reducing conditions. It is clear that methyl substitution on 1- or 2-position inhibits the initial attack by hydroxylation enzymes making them more persistent in the environment and posing longer toxic impact.

AB - Degradation of selected indolic compounds including indole, 1-methylindole, 2-methylindole, and 3-methylindole was assessed under methanogenic and sulfate-reducing conditions using the serum-bottle anaerobic technique and marine sediment from Victoria Harbour, Hong Kong as an inoculum. Our results showed that indole degradation was achieved in 28 days by a methanogenic consortium and 35 days by a sulfate-reducing consortium. During degradation under both conditions, two intermediates were isolated, purified and identified as oxindole and isatin (indole-2,3-dione) suggesting that both methanogenic and sulfate-reducing bacteria use an identical degradation pathway. Degradation processes followed two steps of oxidation accomplished by hydroxylation and then dehydrogenation at 2- and then 3-position sequentially prior to the cleavage of the pyrrole ring between 2- and 3-positions. However, none of 1-methylindole or 2-methylindole was degraded under any conditions. 3-Methylindole (3-methyl-1H-indole, skatole) was transformed under methanogenic conditions and mineralized only under sulfate-reducing conditions. It is clear that methyl substitution on 1- or 2-position inhibits the initial attack by hydroxylation enzymes making them more persistent in the environment and posing longer toxic impact.

KW - Anaerobic degradation

KW - Indole

KW - Metabolic pathway

KW - Methanogenic condition

KW - Substitution

KW - Sulfate-reducing condition

UR - http://www.scopus.com/inward/record.url?scp=0036741558&partnerID=8YFLogxK

U2 - 10.1016/S0025-326X(02)00091-7

DO - 10.1016/S0025-326X(02)00091-7

M3 - 文章

C2 - 12398409

AN - SCOPUS:0036741558

SN - 0025-326X

VL - 45

SP - 379

EP - 384

JO - Marine Pollution Bulletin

JF - Marine Pollution Bulletin

IS - 1-12

ER -