Direct Electrochemical Generation of Catalytically Competent Oxyferryl Species of Classes I and P Dye Decolorizing Peroxidases

This work introduces a novel way to obtain catalytically competent oxyferryl species for
two different dye-decolorizing peroxidases (DyPs) in the absence of H2O2 or any other peroxide
by simply applying a reductive electrochemical potential under aerobic conditions. UV-vis and
resonance Raman spectroscopies show that this method yields long-lived compounds II and I for the
DyPs from Bacillus subtilis (BsDyP; Class I) and Pseudomonas putida (PpDyP; Class P), respectively.
Both electrochemically generated high valent intermediates are able to oxidize ABTS at both acidic
and alkaline pH. Interestingly, the electrocatalytic efficiencies obtained at pH 7.6 are very similar to
the values recorded for regular catalytic ABTS/H2O2 assays at the optimal pH of the enzymes, ca.
3.7. These findings pave the way for the design of DyP-based electrocatalytic reactors operable in an
extended pH range without the need of harmful reagents such as H2O2.