Synthesis of 5-Hydroxymethyl-2-furfurylamine from Bread Waste via Two-Step Reaction

Abstract

5-Hydroxymethyl-2-furfurylamine (HMFA) is an important furan chemical, which plays an important role in diuretics, antihypertensive drugs, and preservatives and can be obtained by amination of 5-hydroxymethylfurfural (HMF). In this study, bread waste (BW) was chemoenzymatically transformed into HMFA via a one-pot two-step method through the tandem catalysis of deep eutectic solvent betaine/formic acid (chemical catalyst) and Escherichia coli HILF cells (biocatalyst). First, the catalyst betaine/formic acid (10.0 wt %) was applied to catalyze BW (20.0 g/L) at 180 °C for 80 min, and the HMF yield reached 0.269 g HMF/g BW. Furthermore, coexpression of ω-transaminase HNIL [His (H) at AT210 was mutated to Asn (N) and Ile (I) at AT77 was mutated to Leu (L) in Aspergillus terreus transaminase] and lactate dehydrogenase (LDH) coupled with formate dehydrogenase (FDH) was utilized for biological amination and coenzyme regeneration, and the recombinant E. coli HILF was constructed by constructing a three-enzyme cascade catalytic reaction system. Using whole cells of HILF as a biocatalyst, the additional amount of d -alanine supplemented into the biological amination reaction was apparently reduced compared with that of the original transaminase. HILF cells could convert BW-derived HMF into HMFA (90.0% yield), and the yield was 0.243 g HMFA/g BW within 6 h. This hybrid strategy apparently reduced the dosage and cost of amine donors in biological amination and also laid the foundation for large-scale production of HMFA from BW.