We find that for LsAA9, the singlet and triplet states are essentially degenerate with both functionals. Similarly, ref. reported that the splittings for LsAA9 are small (< 5.5 kJ/mol) for both functionals (the triplet state was found to be slightly more stable, independent of the functional used). Thus, for this LPMO our results are commensurate with the recent EPR results in ref. , i.e., the triplet state is energetically within reach. The results for TaAA9 are more ambiguous: the triplet state is most stable according to B3LYP (by 9 kJ/mol), whereas