Upcycling of melanoidin-rich Chinese distilled spent grain through solid-state fermentation by Aspergillus awamori

• Published in: Bioresource technology 2025-01, Vol.416, p.131817, Article 131817
• Main Authors: Yang, Shiqi, Arslan-Tontul, Sultan, Fogliano, Vincenzo, Casertano, Melania, Fan, Wenlai, Xu, Yan, Nie, Yao, Vilas-Franquesa, Arnau
• Format: Article
• Language: English
• Subjects: Aspergillus - metabolism; Biomass; China; Chinese liquor; Color; Edible Grain - metabolism; Fermentation; Fungi fermentation; Melanoidin degradation; Polymers - metabolism; Solid waste; Valorization
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2024.131817

[Display omitted] •Chinese distilled spent grain (DSG) is a good substrate for growing A. awamori.•SSF facilitated the solubilization of proteins and phenolic compounds from DSG.•A. awamori effectively degraded DSG melanoidins during SSF.•DSG melanoidins can be converted into A. awamori and A. oryzae biomass. This study investigated the upcycling of distilled spent grain (DSG), a melanoidin-rich by-product of the Chinese liquor industry, via fungal solid-state fermentation (SSF). Two fungi, Aspergillus oryzae and Aspergillus awamori, were tested, with A. awamori growing better on DSG than A. oryzae. SSF with A. awamori increased the concentration of water-soluble protein and phenolic compounds in DSG extracts by 46.5 % and 52.5 %, respectively, and reduced melanoidin level by 73.5 % w/w of DSG, suggesting A. awamori could metabolize melanoidins. Submerged fermentation (SmF) using isolated DSG melanoidins as sole carbon and nitrogen sources confirmed this observation. After 3 days of fermentation, A. awamori and A. oryzae biomass reached 2.5 g/L and 1.5 g/L, quenching melanoidin color by 24.4 % and 12.4 %, respectively. SmF by A. awamori also released free arabinose, glucose, and xylose. Data highlighted the possibility of converting melanoidins into edible mycelia resources, potentially applicable to various melanoidin-rich food by-products.