Sequential solid-state fermentation and hydrothermal carbonization of hempseed oil pomace for the sustainable production of enzymes and hydrocharTišma, Marina (Avtor) Parlov Vuković, Jelena (Avtor) Jednačak, Tomislav (Avtor) Novak, Predrag (Avtor) Zahović, Ida (Avtor) Keršič, Pia (Avtor) Hribernik, Silvo (Avtor) Urbancl, Danijela (Avtor) Čuček, Lidija (Avtor) Petrovič, Aleksandra (Avtor) hempseed oil pomacesolid-state fermentationThermomyces lanuginosusmycelium-based producthydrothermal carbonizationThe valorization of hempseed oil pomace (HP) using two techniques, solid-state fermentation (SSF) and hydrothermal carbonization (HTC), to produce value-added products was investigated. HP was first pretreated with Thermomyces lanuginosus under SSF for 10 days to produce two enzymes (lipase and xylanase) and fermented HP (a nutritionally enriched, mycelium-based product). The structural and chemical properties of the biomass were characterized, and lipase and xylanase activities were monitored daily throughout the fermentation process. Samples collected after 4, 7, and 10 days of fermentation were further subjected to HTC to produce hydrochar (HC) and a liquid fraction (LF), and to study the effect of SSF pretreatment on the properties of HTC products. Structural analysis of fermented HP using NMR, SEM–EDX and FTIR indicated substantial structural modification and partial degradation of the lignocellulosic matrix following SSF pretreatment. High activities of lipase (up to 0.29 U/mL) and xylanase (up to 79.34 U/mL) were obtained during fermentation, while fermented HP exhibited improved nutritional properties, particularly being enriched with free amino acids, among which glutamic and aspartic acids were the most abundant, each exceeding 5000 µg/g. HC from fermented HP exhibited great energetic and fuel properties (calorific values between 28.9 and 29.7 MJ/kg), comparable to HC from non-fermented HP. SSF treatment affected energy yield, volatile matter, and carbon and ash contents, resulting in increased fixed carbon content and an improved fuel ratio. LF obtained from HTC of fermented HP showed reduced toxicity and increased organic acids, total nitrogen and potassium content. Both HC and LF showed potential for fertilizer-oriented applications, although LF would require appropriate dilution or post-treatment before practical use. To the best of the authors’ knowledge, the application of T. lanuginosus for the integrated production of lipase and xylanase, together with the subsequent generation of hydrochar and biofertilizer from hempseed oil pomace or other oilseed pomaces, has not previously been reported.Springer Nature20262026-09-18 12:13:13Članek v reviji100467UDK: 577COBISS_ID: 291366147DOI: 10.1186/s13068-026-02811-0ISSN pri članku: 2731-3654sl