HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Gai, Z. Articles by Xu, P. Search for Related Content PubMed PubMed Citation Articles by Gai, Z. Articles by Xu, P. Agricola Articles by Gai, Z. Articles by Xu, P.

Microbial transformation of benzothiophenes, with carbazole as the auxiliary substrate, by Sphingomonas sp. strain XLDN2-5

Zhonghui Gai^1,

Bo Yu^2,

¹ Key Laboratory of Microbial Metabolism, Ministry of Education, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, PR China
² Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, PR China
³ State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, PR China

Correspondence
Ping Xu
pingxu{at}sjtu.edu.cn

Benzothiophenes are a toxic and relatively recalcitrant fraction of coal-tar creosote. We investigated the co-metabolic transformation of benzothiophene (BT) and its derivatives by the carbazole (CA) degrader Sphingomonas sp. XLDN2-5, which is not able to grow on benzothiophenes as the sole carbon source. Among the benzothiophenes tested, BT, 2-methylbenzothiophene (2-MBT) and 5-methylbenzothiophene (5-MBT) were co-metabolically converted. For 3-methylbenzothiophene, there was complete inhibition of growth on CA. The common transformation products for BT, 2-MBT and 5-MBT are the corresponding sulfoxides and sulfones. For BT, several high-molecular-mass sulfur-containing aromatic compounds, including benzo[b]naphtho[1,2-d]thiophene, benzo[b]naphtho[1,2-d]thiophene-7-oxide, 6a,11b-dihydrobenzo[b]naphtho[1,2-d]thiophene, 6a,11b-dihydrobenzo[b]naphtho[1,2-d]thiophene-7-oxide, and a new product, 6,12-epithiobenzo[b]naphtho[1,2-d]thiophene, were detected by GC-MS. These high-molecular-mass products are thought to be generated from a Diels–Alder-type reaction. Investigations with a combination of GC and flame ionization detection showed that about 17 % of BT was transformed to benzo[b]naphtho[1,2-d]thiophene. Aerobic transformation of benzothiophenes to sulfoxides and sulfones can reduce their toxicity, and facilitate their biodegradation. However, the formation of the high-molecular-mass products, such as benzo[b]naphtho[1,2-d]thiophene, should be considered in the biodegradation of benzothiophenes.

These authors contributed equally to this work.