Monitoring of the yogurt fermentation process based on a rapid bio-luminescent chiral pattern recognition of amino acids.

The analysis of chiral α-amino acids is of great significance in asymmetric synthesis, nutrition, food science, and microbiology. However, the ability of chiral recognition is difficult to achieve. Due to the demand for expensive equipment and skilled operators, traditional methods such as high-performance liquid chromatography are limited. The previously reported methods based on chemical sensor arrays usually cannot carry out the chiral analysis. Here, we developed a novel biosensor array based on the interaction between a suite of host-based luminescent bacteria and amino acids and used linear discriminant analysis to reflect their luminescence response patterns. This biosensor array could effectively discriminate chiral amino acids, including 19 L-amino acids, their corresponding D-enantiomers, and the achiral glycine. In addition, the determination of enantiomeric purity and quantitative ability has been proved. The successful identification of a complex system containing multiple chiral amino acids further demonstrates the superiority of the bioluminescent sensor array. Moreover, this sensor array could efficiently monitor the dynamic composition of free amino acids in the process of milk fermentation. Finally, the bioluminescence response mechanism of the luminescent bacteria for the recognition of chirality was clarified. This approach possessed the advantages of facile construction, high throughput, easy operation, high accuracy and fast response.