Yan Qiao1, Can Wang1, Yin Zeng1, Tairan Wang1, Jingjing Qiao1, Chenze Lu2, Zhao Wang1, Xiangxian Ying3. 1. Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China. 2. College of Life Sciences, China Jiliang University, Hangzhou, 310018, China. 3. Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China. yingxx@zjut.edu.cn.
Abstract
BACKGROUND: α,β-Unsaturated aldehydes are widely used in the organic synthesis of fine chemicals for application in products such as flavoring agents, fragrances and pharmaceuticals. In the selective oxidation of α,β-unsaturated alcohols to the corresponding α,β-unsaturated aldehydes, it remains challenging to overcome poor selectivity, overoxidation and a low atom efficiency in chemical routes. RESULTS: An E. coli strain coexpressing the NADP+-specific alcohol dehydrogenase YsADH and the oxygen-dependent NADPH oxidase TkNOX was constructed; these components enabled the NADP+ regeneration and catalyzed the oxidation of 100 mM 3-methyl-2-buten-1-ol to 3-methyl-2-butenal with a yield of 21.3%. The oxygen supply was strengthened by introducing the hemoglobin protein VsHGB into recombinant E. coli cells and replacing the atmosphere of the reactor with pure oxygen, which increased the yield to 51.3%. To further improve catalytic performance, the E. coli cells expressing the multifunctional fusion enzyme YsADH-(GSG)-TkNOX-(GSG)-VsHGB were generated, which completely converted 250 mM 3-methyl-2-buten-1-ol to 3-methyl-2-butenal after 8 h of whole-cell oxidation. The reaction conditions for the cascade biocatalysis were optimized, in which supplementation with 0.2 mM FAD and 0.4 mM NADP+ was essential for maintaining high catalytic activity. Finally, the established whole-cell system could serve as a platform for the synthesis of valuable α,β-unsaturated aldehydes through the selective oxidation of various α,β-unsaturated alcohols. CONCLUSIONS: The construction of a strain expressing the fusion enzyme YsADH-(GSG)-TkNOX-(GSG)-VsHGB achieved efficient NADP+ regeneration and the selective oxidation of various α,β-unsaturated alcohols to the corresponding α,β-unsaturated aldehydes. Among the available redox enzymes, the fusion enzyme YsADH-(GSG)-TkNOX-(GSG)-VsHGB has become the most recent successful example to improve catalytic performance in comparison with its separate components.
BACKGROUND: α,β-Unsaturatedaldehydes are widely used in the organic synthesis of fine chemicals for application in products such as flavoring agents, fragrances and pharmaceuticals. In the selective oxidation of α,β-unsaturatedalcohols to the corresponding α,β-unsaturatedaldehydes, it remains challenging to overcome poor selectivity, overoxidation and a low atom efficiency in chemical routes. RESULTS: An E. coli strain coexpressing the NADP+-specific alcohol dehydrogenase YsADH and the oxygen-dependent NADPH oxidase TkNOX was constructed; these components enabled the NADP+ regeneration and catalyzed the oxidation of 100 mM 3-methyl-2-buten-1-ol to 3-methyl-2-butenal with a yield of 21.3%. The oxygen supply was strengthened by introducing the hemoglobin protein VsHGB into recombinant E. coli cells and replacing the atmosphere of the reactor with pure oxygen, which increased the yield to 51.3%. To further improve catalytic performance, the E. coli cells expressing the multifunctional fusion enzyme YsADH-(GSG)-TkNOX-(GSG)-VsHGB were generated, which completely converted 250 mM 3-methyl-2-buten-1-ol to 3-methyl-2-butenal after 8 h of whole-cell oxidation. The reaction conditions for the cascade biocatalysis were optimized, in which supplementation with 0.2 mM FAD and 0.4 mM NADP+ was essential for maintaining high catalytic activity. Finally, the established whole-cell system could serve as a platform for the synthesis of valuable α,β-unsaturatedaldehydes through the selective oxidation of various α,β-unsaturatedalcohols. CONCLUSIONS: The construction of a strain expressing the fusion enzyme YsADH-(GSG)-TkNOX-(GSG)-VsHGB achieved efficient NADP+ regeneration and the selective oxidation of various α,β-unsaturatedalcohols to the corresponding α,β-unsaturatedaldehydes. Among the available redox enzymes, the fusion enzyme YsADH-(GSG)-TkNOX-(GSG)-VsHGB has become the most recent successful example to improve catalytic performance in comparison with its separate components.
Authors: Markus Dick; Rudolf Hartmann; Oliver H Weiergräber; Carolin Bisterfeld; Thomas Classen; Melanie Schwarten; Philipp Neudecker; Dieter Willbold; Jörg Pietruszka Journal: Chem Sci Date: 2016-03-30 Impact factor: 9.825