Biogenic amine degrading bacteria as a biotechnological tool for industry application

Biogenic amines (BAs) are nitrogenous compounds derived by microbial decarboxylation of amino acids. They are generally accumulated in fermented foods such as dairy products. Their occurrence could be a food safety risk because they have vasoactive and psychoactive effects, making their reduction a priority in dairy processing. This study explores the ability of 16 Lacticaseibacillus paracasei strains, isolated from Parmigiano Reggiano cheese, to degrade BAs. Strains were tested for the presence of hdc and tdc genes, responsible for histamine and tyramine biosynthesis, respectively. The BAs degradation ability was assessed by HPLC in planktonic and biofilm-preadapted cells and the expression of the multicopper oxidase involved in BAs degradation was evaluated by qRT-PCR. Statistical significance was assessed using one-way ANOVA (P < 0.05), followed by Tukey’s honestly significant difference post hoc test to determine significant pairwise differences between conditions. Three biological replicates and 3 technical replicates were performed to ensure data reliability. The hdc and tdc genes were absent in all strains. The BA degradation rate (%) was higher in biofilm-preadapted cells than in the planktonic counterparts. In particular, L. paracasei LBH01 biofilm-preadapted cells achieved a cadaverine degradation rate of 50.2%, compared with 40.3% in planktonic cells. Similarly, histamine and tyramine degradation reached 33.2% and 36.2%, respectively, in biofilm-preadapted cells. The qRT-PCR analysis confirmed that the mco gene was more expressed in biofilm-preadpated cells than in planktonic ones. The highest overexpression was observed for LBH01 and LBP01 strains with a fold change of 11.9 and 9.4, respectively. These results suggested that the metabolic versatility of L. paracasei biofilm-preadapted cells could be implemented at the industrial level to enhance food safety, reduce regulatory concerns, and improve product quality.