Highly Efficient Chemoenzymatic Cascade Catalysis of Biomass into Furfurylamine by a Heterogeneous Shrimp Shell-Based Chemocatalyst and an ω-Transaminase Biocatalyst in Deep Eutectic Solvent–Water

Recently, the cost-effective production of high value-added furan chemicals from inexpensive, abundant, and renewable bioresources has gained much attention via a chemoenzymatic approach in an environmentally friendly reaction system. Furfurylamine is an important furan-based chemical for the production of additives, fibers, perfumes, agrochemicals, and pharmaceuticals. This study attempted to develop one sustainable approach for the production of furfurylamine via chemoenzymatic cascade catalysis of biomass into furfurylamine using a chemocatalyst and a biocatalyst. Using alkali-treated shrimp shells as the biobased support, a tin-based heterogeneous chemocatalyst (Sn-DAT-SS) was first prepared to transform corncob into furfural in 52.4% yield in deep eutectic solvent choline chloride:ethylene glycol (ChCl:EG)–water (10:90, v/v) at 170 °C within 0.5 h. Sn-DAT-SS was easy to recover and has good reusability. Detailed investigation using Fourier transform infrared (FT-IR) spectroscopy, Brunauer–Emmett–Teller (BET) analysis, temperature-programmed desorption of NH₃ (NH₃-TPD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) indicated that the Lewis and Brönsted acid sites existed on the surface of Sn-DAT-SS. The possible catalytic mechanism of the Sn-DAT-SS-catalyzed transformation of corncob into furfural in ChCl:EG–water was presented. To biologically synthesize furfurylamine, newly constructed recombinant Escherichia coli CCZU-XLS160 whole-cells harboring ω-transaminase and l-alanine dehydrogenase were used to catalyze biomass-derived furfural using available inexpensive NH₄Cl (2.0 mol NH₄Cl/mol furfural) as the amine donor in ChCl:EG–water (10:90, v/v) at 35 °C and pH 7.5. Within 71.5 h, 92.3 mM furfural derived from corncob was wholly transformed into furfurylamine with a productivity of 0.39 g furfurylamine/g xylan in corncob in ChCl:EG–water (10:90, v/v). This work demonstrated an environmentally friendly chemoenzymatic strategy for utilizing lignocellulosic biomass into furfurylamine via tandem chemocatalysis and biocatalysis in green reaction media. It was feasible to obtain furfurylamine from a renewable source consisting of corncob and shrimp shells.