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 limits the 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 environmental friendly, while the bio-toxicity of furan chemicals always hinders the commercial production. By view of a processing-module assembly stratagem, we designed a novel and prospective biotechnology to integrate whole-cell catalysis step, electrodialysis separation step and crystallization/purification step (CCS-EDS-CPS), to achieve a continuous and efficient FA bio-production from bio-toxic furfural by cell catalysis. We found a significant enhancement in the bioconversion productivity (> 10 g/L/h, 98% yield) and cell-recycling, by rapid electrodialysis separation of bio-oxidized FA coupled with continuous feeding of furfural in 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 stratagem, by the processing-module assembly of biotechnology, chemical and electrochemical techniques in term of the bio-oxidation of alcohols to carboxyl acids.