A novel strategy for predicting the quality of a base liquor: visual detection of functional bacteria and its application

Baijiu is the product of the cooperation of a variety of core functional organisms in an open fermentation system. The differences in the structure of these core functional microorganisms are directly related to the quality of the base liquor. <i>Acetilactobacillus jinshanensis</i> is the dominant functional microorganism involved in the process of making Jiang-flavour Baijiu. To quantitatively evaluate the concentration of <i>A. jinshanensis</i> in the fermentation system, a CRISPR/Cas12a-coupled gold nanoparticle visual biosensor was developed. The limit of detection for <i>A. jinshanensis</i> was as low as 1 copy/μL, and its sensitivity exceeded that of the existing quantitative real-time PCR method. Furthermore, this system was employed to determine the concentration of <i>A. jinshanensis</i> during actual Baijiu fermentation. The average fluorescence value of <i>A. jinshanensis</i> in excellent-grade workshop was 4838, while that in ordinary workshops was 2145. The results revealed a linear relationship (R² = 0.845) between the quality of the base liquor and the concentration of <i>A. jinshanensis</i> was obtained. Therefore, the concentration of <i>A. jinshanensis</i> might be used as a new parameter to predict the quality of base liquor and as a regulatory target in the fermentation process, thereby achieving a controllable fermentation process and high quality.