Comparative genomics reveals the potential biotechnological applications of Liquorilactobacillus nagelii VUCC-R001, a strain isolated from kombucha tea

Liquorilactobacillus nagelii is a lactic acid bacterium frequently found in a variety of traditional fermented foods, where it contributes to their sensory properties and potential health benefits. However, research evaluating the genetic and functional features of L. nagelii is scarce in the literature. In this study, we sequenced and assembled the genome of L. nagelii VUCC-R001, a strain isolated from kombucha tea, assessing its safety and exploring its biotechnological potential, mainly in terms of d-phenyllactic acid and dextran production, through a comparative genomic approach with 35 Liquorilactobacillus genomes and related phenotypic validation. Bioinformatic analysis revealed a good-quality draft genome (∼2.4 Mb) of VUCC-R001 with a completeness around 99.7% (N50 of 151,630 bp). Comparative genomic analyses showed the correct identification of the new strain, the absence of genes encoding transmissible antibiotic resistance, virulence factors, and biogenic amine production, underlining its safety, also confirmed by phenotypic tests. We identified genes putatively associated with d-phenyllactic acid (PLA) production and verified the capability of this strain to produce a high concentration (52 mg/L) of PLA in vitro. To date, this is the first study reporting a Liquorilactibacillus strain that produces d-phenyllactic acid. Genome analyses of L. nagelii also elicited the presence of a dextransucrase GH70 (EC 2.4.1.5), leading to the production of dextran from sucrose, an exopolysaccharide with applications in the food and biomedical industries. This investigation provides new insights into the genomic features and functional attributes of L. nagelii, opening new prospects for the biotechnological use of selected strains belonging to this species.