Whole-cell selective oxidation of 5-HMF by sugarcane bagasse isolated Bacillus nitratireducens

Abstract

This study delves into the biocatalytic oxidation of 5-hydroxymethylfurfural (5-HMF) by the newly isolated Bacillus nitratireducens, from sugar cane bagasse. This reaction remains unexplored within the existing scientific literature concerning this microbial strain. Initially, to comprehensively characterize the strain and classify it taxonomically, genotypic and phenotypic analysis were conducted, including whole genome sequencing and ANI analysis. Subsequently, the study proceeded to evaluate for the first time with B. nitratireducens the efficiency of 5-HMF oxidation under aerobic conditions. The process resulted in the formation of 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) as the principal product, a valuable molecule that demonstrates promising potential as a precursor for polyesters. Additionally, the compound exhibits medical applications, including its role as an anti-tumor agent and interleukin inhibitor. Employing Response Surface Methodology (RSM), the conditions conducive to optimizing HMFCA production were assessed. These conditions, including a 3 mM 5-HMF concentration, a pH level of 5.6, and a temperature of 30°C maintained over a period of 24 hours, were found to yield optimal results. Model validation further underscored the effectiveness of these conditions, demonstrating a 91% HMFCA yield, which slightly exceeded the predicted 88%. In conclusion, the study highlights the potential of the biomass-derived Bacillus strain in achieving a high conversion rate through the selective oxidation of the aldehyde group present in the 5-HMF molecule. This whole-cell catalytic process eliminates the need for noble metal catalysts, commonly employed in similar chemical reactions, thereby underscoring its potential for enhancing environmental sustainability and reducing reliance on costly and potentially harmful catalysts.