The processing-module assembly strategy for continuous bio-oxidation of furan chemicals by integrated and coupled biotechnology

Abstract

Furoic acid (FA), a highly valuable intermediate from furfural, is widely used in the resin, plastic, food, and pharmaceutical industries. Currently, FA synthesis involves the oxidation of furfural by O₂, catalyzed by noble metals, but the high-cost and low selectivity limit its industrial-scale production. Gluconobacter oxydans mediated FA bio-production by whole-cell catalysis of furfural presents a promising approach with advantages of high selectivity, safety, and environmentally friendly nature, while the bio-toxicity of furan chemicals always hinders their commercial production. In view of a processing-module assembly strategy, we designed a novel and prospective biotechnology to integrate the whole-cell catalysis step, electrodialysis separation step and crystallization/purification step (CCS–EDS–CPS) to achieve continuous and efficient FA bio-production from bio-toxic furfural by whole-cell catalysis. We found a significant enhancement in bioconversion productivity (>10 g L⁻¹ h⁻¹, 98% yield) and cell-recycling by rapid electrodialysis separation of bio-oxidized FA coupled with continuous feeding of furfural in the CCS, which alleviated the bio-toxicity of furan chemicals. Meanwhile, the highly pure FA end-product was spontaneously crystallized and precipitated at room temperature by the enrichment effect of EDS. Thus, the integrated and coupled method presents an advanced technical strategy using the processing-module assembly of biotechnology, and chemical and electrochemical techniques for the bio-oxidation of alcohols into carboxyl acids.