Anaerobic biodecolorization mechanism of methyl orange by Shewanella oneidensis MR-1.

Pei-Jie Cai, Xiang Xiao, Yan-Rong He, Wen-Wei Li, Jian Chu, Chao Wu, Meng-Xing He, Zhe Zhang, Guo-Ping Sheng, Michael Hon-Wah Lam, Fang Xu, Han-Qing Yu

Department of Chemistry, University of Science & Technology of China, Hefei, China.

Applied microbiology and biotechnology 2012 Feb

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In this work, we investigated the anaerobic decolorization of methyl orange (MO), a typical azo dye, by Shewanella oneidensis MR-1, which can use various organic and inorganic substances as its electron acceptor in natural and engineered environments. S. oneidensis MR-1 was found to be able to obtain energy for growth through anaerobic respiration accompanied with dissimilatory azo-reduction of MO. Chemical analysis shows that MO reduction occurred via the cleavage of azo bond. Block of Mtr respiratory pathway, a transmembrane electron transport chain, resulted in a reduction of decolorization rate by 80%, compared to the wild type. Knockout of cymA resulted in a substantial loss of its azo-reduction ability, indicating that CymA is a key c-type cytochrome in the electron transfer chain to MO. Thus, the MtrA-MtrB-MtrC respiratory pathway is proposed to be mainly responsible for the anaerobic decolorization of azo dyes such as MO by S. oneidensis.

Citation

Pei-Jie Cai, Xiang Xiao, Yan-Rong He, Wen-Wei Li, Jian Chu, Chao Wu, Meng-Xing He, Zhe Zhang, Guo-Ping Sheng, Michael Hon-Wah Lam, Fang Xu, Han-Qing Yu. Anaerobic biodecolorization mechanism of methyl orange by Shewanella oneidensis MR-1. Applied microbiology and biotechnology. 2012 Feb;93(4):1769-76