Findinf of novel decarboxylases which catalyzes carbon dioxide fixation and establishment of the precise conversion techniques of carbon dioxide

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Due to the abundance of CO2 as the major greenhouse gas and C-C-bond-formlng properties, CO2-flxing enzymes are of high interest. Recently, it is revealed that a certain group of decarboxylases can catalyze carboxylation by their reverse reaction. We have found that pyrrole-2-carboxylase efficiently catalyzes the carboxylation of pyrrole to pyrrole-2-carboxylic acid. In addition, recently we also found that indole-3carboxylate decarboxylase catalyzes the carboxylation of indole to indole-3-carboxylate. Pyrrole-2-carboxylate decarboxylase from BacMus megaterium PRY2910 attains a balanced reaction quilibrium with an equilibrium constant of 0.3-0.4 M. Therefore, saturating amounts of KHCO3 ( 3 M ) were used leading to a shift of the reaction equilibrium towards pyrrole-2-carboxylic acid. The increased pressure supported the reverse reaction productivity 2.5-fold compared to atmospheric pressure. In a batch reactin, 300 mM pyrrole'were converted to 230 mM (25.5 g/1) pyrrole-2-carboxylate. The productivity was increased to 325 mM ( 36. 1 g/1 ) by feeding 150 mM pyrrole after 3 h to a reaction with initially 250 mM pyrrole. The bioconversion yield was limited to 77-81 % due to the reaction equilibrium. Pyrrole-2-carboxylate decarboxylase and indole-3-carboxylate decarboxlase were purified and characterized. We could find some similarity. Their gene analyzes were also carrried out.