Whole-Cell Biocatalytic Production of 2,5-Furandicarboxylic Acid from 5-Hydroxymethylfurfural by Bacillus subtilis J8M8

2,5-Furandicarboxylic acid (FDCA) is an important bio-based platform compound that can be synthesized through the biotransformation of 5-hydroxymethylfurfural (HMF). However, the limited availability of safe microbial strains is a major constraint in the whole-cell catalysis of HMF to FDCA. In this study, a strain capable of catalyzing the conversion of HMF to FDCA, Bacillus subtilis J8M8, was identified. Under optimized whole-cell catalytic conditions, the wild-type strain produced 33.1 mM FDCA with a yield of 41.4%. To enhance FDCA production, HMF/furfural oxidoreductase (HmfH), PQQ-dependent alcohol dehydrogenase (ADH), and aryl-alcohol oxidase (MaAAO) were co-expressed in B. subtilis J8M8. As a result, FDCA production increased to 72.3 mM, with a yield of 90.4%. Further optimization of the engineered strain improved FDCA production to 83.3 mM and yield to 92.6%, representing a 2.52-fold increase over that of the wild-type strain. This study establishes a foundation for the safe and sustainable production of FDCA from HMF.