Fixation of gaseous CO2 by reversing a decarboxylase for the biocatalytic synthesis of the essential amino acid l-methionine

摘要

in industrial biotechnology due to the complexity and costly energy balance of conventional anabolic biosynthesis. Here, we describe the biocatalytic preparation of l-methionine from the abundant industrial intermediate methional under direct incorporation of CO2 by reversing the catabolic Ehrlich pathway. Despite unfavourable chemical equilibrium (1/554 M~(-1)), the decarboxylase KdcA revealed half-maximal activity for its reverse reaction at astonishingly low CO2 pressure (320 kPa). Accordingly, it was possible to synthesize l-methionine under a 2 bar CO2 atmosphere when coupled to an energetically favourable transaminase or amino acid dehydrogenase reaction. Similarly, L-leucine and L-isoleucine were prepared via biocatalytic carboxylation of 3- or 2-methylbutanal, respectively. Our findings open a biotechnological route towards industrial products and enable further syntheses involving the fixation of gaseous CO2 by simply applying decarboxylases in the reverse mode.