Icariside I, a bioactive flavonoid derivative derived from Herba epimedii, demonstrates better pharmacological properties compared to its precursor icariin. Enzymatic conversion of icariin to icariside I using α-L-rhamnosidase represents an efficient biotechnological approach. In this study, we characterized a GH78 family α-L-rhamnosidase from Dictyoglomus thermophilum (DthRha) with promising biocatalytic properties. The recombinant DthRha displayed optimal activity at 55 °C and pH 6.0, with remarkable thermostability (retaining > 80% activity after 1 h at 45–65 °C) and pH stability (pH 5.0–7.0). The kinetic parameters K_m, k_cat and k_cat/K_m values for pNPR of 0.44 mM, 7.99 s⁻¹ and 18.16 s⁻¹ mM⁻¹, respectively. Notably, DthRha exhibited good organic solvent tolerance, retaining > 50% activity after 4 h in 10% DMSO. Applied in a DMSO cosolvent system, DthRha achieved 92.3% conversion of icariin to icariside I within 4 h under optimized conditions. Interestingly, elevating the substrate concentration to 10 mM resulted in a consistently high icariin conversion of 95.8%. The enzymatic hydrolysis method can be applied to the industrial production of Icariside I. Furthermore, DthRha not only cleaves the α-1,2 glycosidic bond between glucoside and rhamnoside in compounds like naringin, but also exhibits tolerance to organic solvents, making it suitable for the hydrolysis of other poorly soluble flavonoids.

Icariside I is a pharmacologically important prenylated flavonoid glycoside, yet its efficient biocatalytic production from icariin is hindered by the limited stability and recyclability of the enzymes involved. In this study, an α-L-rhamnosidase mutant R783A (Rha R783A) was heterologously expressed, purified, and immobilized within a Cu-based metal–organic framework (MOF) via a one-pot co-precipitation strategy. The resulting Rha R783A@MOF biocomposite exhibited enhanced stability compared to the free enzyme, retaining >90% residual activity after incubation at 60 °C for 2 h and 86.4% after 30 days of storage. It also demonstrated broad pH adaptability. In the biotransformation of icariin, Rha R783A@MOF achieved a 99.8% conversion rate and a 97.8% yield of icariside I. Furthermore, the biocomposite maintained an 88.9% yield after eight consecutive reuse cycles under high-temperature conditions (60 °C), demonstrating excellent operational stability. This work presents a robust and sustainable strategy for icariside I production, highlighting the potential of MOF microparticles as an effective platform for the biocatalytic synthesis of high-value flavonoid compounds.