Chemoenzymatic valorization of agricultural wastes into 4-hydroxyvaleric acid via levulinic acid

[Display omitted] •LA was produced from agricultural wastes with concentrations of 25.1 to 65.4 mM.•eHBDH catalyzed agricultural waste-driven LA to 4-HV with conversion rate of 48.2%.•Through chemoenzymatic valorization, maximum 11.3 mM 4-HV was obtained.•Co-produced formate was used as a H2 source for the conversion of LA to 4-HV.•This is the first report of 4-HV production from actual lignocellulosic biomass. Given that (i) levulinic acid (LA) is one of the most significant platform chemicals derived from biomass and (ii) 4-hydroxyvaleric acid (4-HV) is a potential LA derivative, the aim of this study is to achieve chemoenzymatic valorization of LA, which was obtained from agricultural wastes, to 4-HV. The thermochemical process utilized agricultural wastes (i.e., rice straw and corncob) as feedstocks and successfully produced LA, ranging from 25.1 to 65.4 mM. Additionally, formate was co-produced and used as a hydrogen source for the enzymatic hydrogenation of LA. Finally, engineered 3-hydroxybutyrate dehydrogenase from Alcaligenes faecalis (eHBDH) was applicable for catalyzing the conversion of agricultural wastes-driven LA, resulting in a maximum concentration of 11.32 mM 4-HV with a conversion rate of 48.2%. To the best of our knowledge, this is the first report describing the production of 4-HV from actual biomass, and the results might provide insights into the valorization of agricultural wastes.