Malt extract

2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), bulk CuCO₃·Cu(OH)₂, CuSO₄, TBA and TTM were purchased from Sigma Aldrich, while agar, malt extract and potassium chloride from VWR (Oxoid, Darmstadt, Germany).
The oxalic acid assay Enzytec oxalic acid was purchased from R-Biopharm AG. The silver stain kit, Dodeca Silver Stain was obtained from BIO-RAD.
Two commercial aqueous suspensions of MCA were investigated. The two MCA formulations contain comparable amounts of Cu particles but differ in the amount of TBA: MCA_HTBA contained 5% w/w and MCA_LTBA 0.4% w/w TBA.

Ultrapure water (conductivity 18.2 mΩ) was used in all experiments. For fungal cultures, malt extract was purchased from VWR, EDTA-Na₂ and glucose were from Sigma, (NH₄)₂SO₄ and CaCl₂ were from Panreac, H₃BO₃, MnCl₂, FeSO₄, CuSO₄, CoCl₂ Na₂MoO₄, MgSO_4, KH₂PO₄, and ZnSO₄ were purchased from Prolabo and Bacto agar was purchased from Fischer.
For analytic methods, CD₃OH, HPLC grade organic acid standards (acetic, adipic acid, L-ascorbic acid, benzoic acid, butyric acid, citric acid, isobutyric acid, formic acid, fumaric acid, L-(+)-lactic acid, DL-isocitric acid trisodium salt hydrate, maleic acid, malonic acid, D-(+)-malic acid, oxalic acid, phytic acid, propionic acid, (−)quinic, succinic acid, shikimic acid,D-(−)-tartaric acid), methylchloroformate (MCF), and glucose were purchased from Sigma, HPLC grade ethanol was purchased from Fluka. Dichloromethane was from Carlo Erba Reagents.