Carboligation of 5-(hydroxymethyl)furfural via whole-cell catalysis to form C12 furan derivatives and their use for hydrazone formation

Background Biobased 5-(hydroxymethyl)furfural (5-HMF) is an important platform that offers numerous possibilities for upgrading to a range of chemical, material and fuel products. One reaction of special interest is the carboligation of 5-HMF into C 12 compounds, including 5,5’-bis(hydroxymethyl)furoin (DHMF) and its subsequent oxidation to 5,5’-bis(hydroxymethyl)furil (BHMF), due to their potential applications as building blocks for polymers and hydrocarbon fuels. Objectives This study was aimed at evaluating the use of whole cells of Escherichia coli carrying recombinant Pseudomonas fluorescens benzaldehyde lyase as biocatalysts for 5-HMF carboligation, recovery of the C 12 derivatives DHMF and BHMF, and testing the reactivity of the carbonyl groups for hydrazone formation for potential use as cross-linking agents in surface coatings. The effects of different parameters on the reaction were investigated to find the conditions for achieving high product yield and productivity. Results The reaction with 5 g/L 5-HMF using 2 g CDW /L recombinant cells in 10% dimethyl carbonate, pH 8.0 at 30 °C resulted in DHMF yield of 81.7% (0.41 mol/mol) at 1 h, and BHMF yield of 96.7% (0.49 mol/mol) at 72 h reaction time. Fed-batch biotransformation generated a maximum DHMF concentration of 53.0 g/L (or 26.5 g DHMF/g cell catalyst) with productivity of 10.6 g/L . h, after five feeds of 20 g/L 5-HMF. Both DHMF and BHMF reacted with adipic acid dihydrazide to form hydrazone that was confirmed by Fourier-transform infrared spectroscopy and 1 H NMR. Conclusion The study demonstrates the potential application of recombinant E. coli cells for cost-effective production of commercially relevant products.