Conversion of high-value products from biomass aqueous phase through enzymatic-hydrothermal treatment

Hydrothermal treatment is a beneficial method for the resource utilization of biomass waste, producing hydrochar and an aqueous phase containing valuable organic products. However, the pathway for recovering high-value products from the aqueous phase remain insufficiently explored. This work presents an innovative enzymatic-hydrothermal treatment designed to enrich the concentration of nitrogen-containing compounds in the hydrothermal aqueous phase (AP) derived from nitrogen-rich biomass. A detailed analysis of the post-enzymatic AP products was carried out, with a specific emphasis on tracking changes in the chemical composition of the AP. The results showed a significant increase in the nitrogen content of the soymeal-derived AP after enzymatic pre-treatment followed by hydrothermal treatment at 220 °C. Meanwhile, valuable platform compounds such as furfural and 5-hydroxymethylfurfural were produced via isophorone-catalyzed decarboxylation of α-amino acids within the enzymatic soymeal AP, steered by deliberate modifications in the reaction pathway. Moreover, a working mechanism for this catalytic decarboxylation process was proposed, enabling precise adjustments to the composition of the AP.