Systematic engineering of phytochelatin synthesis and arsenic transport for enhanced arsenic accumulation in E. coli |
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| Authors: | Shailendra Singh Seung Hyun Kang Wonkyu Lee Ashok Mulchandani Wilfred Chen |
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| Affiliation: | 1. Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521;2. telephone: 951‐827‐2473: fax: 951‐827‐5696;3. Cell Molecular & Developmental Biology Graduate Program, University of California, Riverside, California 92521 |
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| Abstract: | Phytochelatin (PC) is a naturally occurring peptide with high affinity towards arsenic (As). In this article, we demonstrated the systematic engineering of PC‐producing E. coli for As accumulation by addressing different bottlenecks in PC synthesis as well as As transport. Phytochelatin synthase from Schizosaccharomyces pombe (SpPCS) was expressed in E. coli resulting in 18 times higher As accumulation. PC production was further increased by co‐expressing a feedback desensitized γ‐glutamylcysteine synthetase (GshI*), resulting in 30‐fold higher PC levels and additional 2‐fold higher As accumulation. The significantly increased PC levels were exploited further by co‐expressing an arsenic transporter GlpF, leading to an additional 1.5‐fold higher As accumulation. These engineering steps were finally combined in an arsenic efflux deletion E. coli strain to achieve an arsenic accumulation level of 16.8 µmol/g DCW, a 80‐fold improvement when compared to a control strain not producing phytochelatins. Biotechnol. Bioeng. 2010. 105: 780–785. © 2009 Wiley Periodicals, Inc. |
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| Keywords: | heavy metals arsenic bioremediation glutathione phytochelatins |
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