Rapid detection of Bacillus subtilis in complex fermentation environment by robust and efficient dual-ligand...

Bacillus subtilis is one of the dominant bacteria in high-temperature Daqu of jiang-flavor baijiu. The heat-resistant enzymes and pyrazine compounds produced by Bacillus subtilis are crucial to the formation of jiang flavor. This study introduced a highly sensitive and specific biosensor for the detection of B. subtilis based on a boronic acid/amino-functionalized metal-organic framework and aptamer. The biosensor consists primarily of two parts, a biological recognition unit (boronic acid and aptamer) and a fluorescence output unit, which can accurately quantify the signal of B. subtilis by fluorescence intensity. The aptamer-modified magnetic beads specifically captured B. subtilis, and the enriched bacteria were recognized and detected by dual-ligand metal-organic frameworks. The biosensor can rapidly quantify B. subtilis in the range of 25-10⁸ CFU/mL with a low limit of detection (9 CFU/mL) and excellent specificity, repeatability, and stability, providing an effective technical solution for addressing microbial detection challenges in real production scenarios.