Suchy, L., & Rudroff, F. (2021, July). Synthesis of α-Hydroxyketones, Primary, and Secondary Amines via Reactive Aldehyde Intermediates in E. coli [Poster Presentation]. Biotrans 2021, Graz, Austria.
Biocatalysis; In vivo enzymatic cascade; E. coli; Redox equilibrium
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Abstract:
Synthetic enzyme cascades in living cells offer a great possibility for the production of value-added chemicals. Hereby, aldehydes represent valuable intermediates and precursors for numerous chemical compounds. However, highly reactive aldehyde species are toxic to the organism which leads to the formation of undesired byproducts (the respective alcohols and carboxylic acids) by endogenous enzyme activities. Previous research has shown that when applying whole-cell biocatalysis, primary alcohols and carboxylic acids can be converted into aldehydes by alcohol dehydrogenases (AlkJ, P. putida) and carboxylic acid reductase (CARNi, N. iowensis, co-expressed with PPtaseEc for posttranslational modification of CARNi) respectively in E. coli resting cells. At the same time, the aldehyde is freely available for further reaction. To expand the spectrum of this concept and to prove that it can be applied to synthesise a wide range of compounds, new enzyme classes were incorporated into the cascade: A pyruvate decarboxylase (PDCAp_mutant, A. pasteurianus), w-transaminases (w-TAVf, V. fluvialis) and imine reductase (IREDCf, C. ferrugineus). For the co-expression of the pathway enzymes, the genes of interest were combined via molecular cloning and co-transformation of two plasmids. After confirmation of co-production of the enzymes, three new biocatalytic pathways were tested. Either the alcohol or the carboxylic acid was employed as starting material for the cascade reaction. In this way, the biocatalytic concept was expanded to yield α-hydroxy ketones, primary, and secondary amines as final cascade products.
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Research Areas:
Biological and Bioactive Materials: 40% Sustainable Production and Technologies: 40% Efficient Utilisation of Material Resources: 20%