Genetic and enzymatic profiling reveals aminopeptidase potential of Lactobacillus acidophilus ItalPN270.

Abstract

Lactobacillus acidophilus strains are considered probiotics and have several industrial applications, including their use as non-starter cultures in fermented milk products. However, their biotechnological potential was partially explored. This work investigated the potential peptidase activity of Lactobacillus acidophilus ItalPN270, by mining their whole genome for genetically encoded peptidases and a comparative in vitro analysis of aminopeptidase activity and lytic behavior. The results showed that the assembled bacterial genome comprised one circular chromosome (1 964 524 bp) with 34.57% GC content, and 1906 protein-coding sequences (CDSs). Analysis of the genome sequence of ItalPN270 revealed the presence of 25 genes that encode peptidases with different specificities. The ItalPN270 presented higher values of aminopeptidase activity in vitro, regarding the six enzymatic substrates evaluated, showing values of total aminopeptidase activity 4-fold higher, as compared with an L. paracasei and L. helveticus strains, and notable high activity of pepA, pepL, and pepX. Moreover, the strain ItalPN270 showed an autolysis profile defined by 63.4% of lysis in the first 5 days with low variations after 40 days at 13°C. Thus, our results indicated that strain L. acidophilus ItalPN270 is a potential source of peptidases for different applications, including as adjunct bacteria for improving cheese ripening.