Comprehensive analysis of the metabolic and genomic features of tannin transforming Lactiplantibacillus plantarum strains

Extracellular tannase Lactiplantibacillus plantarum-producing strains (TanA+) release bioactive metabolites from dietary tannins. However, there is a paucity of knowledge of TanA+strains and their hydrolyzing capacities. This study aimed to shed light on the metabolic and genomic features of TanA+L. plantarum strains and to develop a screening technique. The established spectrophotometric was validated by UPLC-UV-QToF. Eight of 115 screened strains harbored the tanA gene, and six presented TanA activity (PROBI S126, PROBI S204, RKG 1-473, RKG 1-500, RKG 2-219, and RKG 2-690). When cultured with tannic acid (a gallotannin), TanA+strains released 3.2-11 times more gallic acid than a lacking strain (WCFS1) (p<0.05). TanA+strains with gallate decarboxylase (n=5) transformed this latter metabolite, producing 2.2-4.8 times more pyrogallol than the TanA lacking strain (p<0.05). However, TanA+strains could not transform punicalagin (an ellagitannin). Genomic analysis revealed high similarity between TanA+strains, as only two variable regions of phage and polysaccharide synthesis were distinguished. A phylogenetic analysis of 149 additional genome sequences showed that tanA harboring strains form a cluster and present two bacteriocin coding sequences profile. In conclusion, TanA+L. plantarum strains are closely related and possess the ability to resist and transform gallotannins. TanA can be screened by the method proposed herein.

Automated summary

This study revealed the metabolic and genomic features of TanA+L. plantarum strains and developed a screening technique. The results showed that these strains have the ability to resist and transform gallotannins.