Background: Acetaldehyde dehydrogenase (ALDH) is a common oxidoreductase and one of the aldehyde dehydrogenases, which can convert toxic acetaldehyde to harmless acetyl CoA. Results: A novel acetaldehyde dehydrogenase (LpALDH) from Lactiplantibacillus plantarum was obtained by gene mining and then was analyzed by a series of bioinformatics software. Phylogenetic tree results showed that LpALDH was highly homologous with acetaldehyde dehydrogenase derived from Pediococcus sp., and their sequence similarity was 62.9%. Moreover, it was successfully expressed in Escherichia coli BL21, its expression level was 195 U/mL, which was about 600 times than that expressed in L. plantarum. After purification by affinity chromatography, the specific activity of reLpALDH was 1709 U/mg. Its tem-perature optimum was 35 degrees C, and the optimal reaction pH was 8.0. Moreover, the purified LpALDH showed good stability in simulated gastrointestinal fluids, which indicated that it had great potential in functional food additive field. Conclusions: This research also laid a solid foundation for further molecular modification, optimal expres-sion host selection and application of acetaldehyde dehydrogenases. How to cite: Wang Z, He J, Liu X, et al. High-level expression of an acetaldehyde dehydrogenase from Lactiplantibacillus plantarum and preliminary evaluation of its potential as a functional food additive. Electron J Biotechnol 2023;63. https://doi.org/10.1016/j.ejbt.2022.12.005. CO 2023 Pontificia Universidad Catolica de Valparaiso. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).