Development of an advanced acetaldehyde detection solution based on yeast and bacterial surface display technology.

Abstract

Acetaldehyde, a carcinogen widely present in various beverages and the natural environment, necessitates convenient and efficient detection methods. In this work, two different host strains were used to develop a sensitive, convenient, and efficient whole-cell optical biosensor for acetaldehyde detection. Acetaldehyde dehydrogenase (AldH) was displayed on the cell surface of Saccharomyces cerevisiae and E. coli using flocculin protein and the N-terminal ice nucleation protein (INP), respectively. The successful construction of yeast and bacteria surface display platforms was confirmed by laser scanning confocal microscopy. Then, the optimal AldH-display system for yeast and bacteria was confirmed. The optimum reaction conditions were determined by changing testing temperatures and pH values. The differences between the two display systems were compared. The highest whole-cell activities of yeast and bacteria under optimal conditions were 3.68 ± 0.07 U/mL/OD₆₀₀ for BY-S6G and 6.95 ± 0.04 U/mL/OD₆₀₀ for E-32-I_rA. The strains with the best performance were chosen for the detection of acetaldehyde in wine and other beverage samples and showed substrate specificity and accuracy, in which the recovery rate ranged between 94.4 % and 110.1 %. The results demonstrated that the AldH surface display strains could be used as an optical biosensor to detect acetaldehyde in beverages and red wine.