Exploration Of Benign Deep Eutectic Solvent-Water Systems For The Highly Efficient Production Of Furfurylamine From Sugarcane Bagasse Via Chemoenzymatic Cascade Catalysis

Recently, cost-effective production of high value-added furan chemicals from abundant and renewable bioresources has attracted much attention via a chemoenzymatic approach in an environmentally friendly reaction system. In this work, a chemoenzymatic cascade reaction for bridging tandem chemocatalysis and biocatalysis was constructed to valorize biomass into furfurylamine in a deep eutectic solvent (DES)-water system. Waste shrimp shell (SS) was used as a biobased carrier to prepare sulfonated tin-based solid acid (Sn-SS) for catalyzing sugarcane bagasse (SB) into furfural in DES-water. The prepared Sn-SS was characterized by XRD, SEM, FTIR spectroscopy and BET. Furfural (113.2 mM) was obtained in 62.3% yield from xylan in SB by Sn-SS (0.6 wt% dose) within 20 min at 170 degrees C in [ChCl][EG]-water (20 : 80, v : v). A potential catalytic mechanism was proposed for catalyzing SB into FAL and derivatives in [ChCl][EG]-water. Sequentially, one newly constructed recombinant Escherichia coli PRSFDuet-CV-AlaDH cells containing omega-transaminase and l-alanine dehydrogenase were used for the biological transamination of SB-derived furfural to furfurylamine in the presence of amine donor NH4Cl (2.0 mol NH4Cl/mol furfural) and cosubstrate glucose (1.0 mol glucose/mol furfural) at 35 degrees C and pH 8.0 without the removal of Sn-SS and residual SB. Within 1 h, SB-derived furfural was wholly aminated to furfurylamine with a productivity of 0.458 g furfurylamine per g xylan in SB by whole cells using NH4Cl as an amine donor in [ChCl][EG]-water (20 : 80, v : v). It was found that [ChCl][EG]-water enhanced furfural and furfurylamine yields. Compared to the aqueous system, this green [ChCl][EG]-water (20 : 80, v : v) system enabled the highly efficient production of furfurylamine from SB via chemoenzymatic cascade catalysis with a sulfonated Sn-SS catalyst and omega-transaminase biocatalyst by enhancing the catalytic activity and thermostability of chemocatalysts and biocatalysts. This chemoenzymatic cascade reaction strategy had potential application for utilizing renewable biomass into furan-based chemicals in the benign DES-water system.