“…However, weak acids, mostly acetic, formic and oxalic, are usually present as the principal inhibitors generated from the ozonolysis of biomass. Aromatic aldehyde and acids including p-hydroxybenzaldehyde, vanillin, vanillic acid, caproic acid, azelaic acid and p-hydroxybenzoic acid were also present in oxidation products of p-coumaric and ferulic acids from lignin [8,17,26,50]. Ozonation of wheat straw using 40% moisture 60 L/h air/ozone flow rate, 2.7% ozone concentration, and 2 h pretreatment time generated 4.14 g oxalic acid/100 g dry matter, and 0.98 g acetic acid/100 g dry matter [51].…”