This study characterized the enzymatic ability of a cell-free extract from an acidophilic (+)-catechin degrader Burkholderia oxyphila (OX-01). The crude OX-01 extracts were able to transform (+)-catechin and (-)-epicatechin into (+)-taxifolin via a leucocyanidin intermediate in a two-step oxidation. Enzymatic oxidation at the C-4 position was carried out anaerobically using H2O as an oxygen donor. The C-4 oxidation occurred only in the presence of the 2R-catechin stereoisomer, with the C-3 stereoisomer not affecting the reaction. These results suggest that the OX-01 may have evolved to target both (+)-catechin and (-)-epicatechin, which are major structural units in plants.
Keywords: (+)-catechin; (+)-taxifolin; (−)-epicatechin; burkholderia; enzymatic reaction.