Spent auricularia auricular substrate (SAAS) was oxidatively degraded with aqueous hydrogen peroxide (AHPO)/acetic anhydride (AAH) to produce carboxylic adds (CAs) under mild conditions. The results show that up to 53.6% of the organic matter in SAAS was converted to the soluble species (SSs). In total 122 CAs were detected in the SSs by the analysis with a gas chromatograph/mass spectrometer, which can be classified into 29 group components, mainly being aliphatic acids and along with small amount of aromatic adds. Among the aliphatic adds, normal alkanedioic acids are the most abundant. The detected aromatic acids include benzoic adds, phthalic adds, trimellilic adds, pyromellilic acids, and their derivatives. The synergistic oxidation and the released center dot OH, CH3COO center dot, and HOO center dot induced by AHPO/AAH play crucial roles in oxidatively degrading SAAS. (C) 2019 The Chemical Industry and Engineering Society of China. and Chemical Industry Press Co.. Ltd. All rights reserved.