Metabiotics Signature through Genome Sequencing and In Vitro Inhibitory Assessment of a Novel Lactococcus lactis Strain UTNCys6-1 Isolated from Amazonian Camu-Camu Fruits

Abstract

Metabiotics are the structural components of probiotic bacteria, functional metabolites, and/or signaling molecules with numerous beneficial properties. A novel Lactococcus lactis strain, UTNCys6-1, was isolated from wild Amazonian camu-camu fruits (Myrciaria dubia), and various functional metabolites with antibacterial capacity were found. The genome size is 2,226,248 base pairs, and it contains 2248 genes, 2191 protein-coding genes (CDSs), 50 tRNAs, 6 rRNAs, 1 16S rRNA, 1 23S rRNA, and 1 tmRNA. The average GC content is 34.88%. In total, 2148 proteins have been mapped to the EggNOG database. The specific annotation consisted of four incomplete prophage regions, one CRISPR-Cas array, six genomic islands (GIs), four insertion sequences (ISs), and four regions of interest (AOI regions) spanning three classes of bacteriocins (enterolysin_A, nisin_Z, and sactipeptides). Based on pangenome analysis, there were 6932 gene clusters, of which 751 (core genes) were commonly observed within the 11 lactococcal strains. Among them, 3883 were sample-specific genes (cloud genes) and 2298 were shell genes, indicating high genetic diversity. A sucrose transporter of the SemiSWEET family (PTS system: phosphoenolpyruvate-dependent transport system) was detected in the genome of UTNCys6-1 but not the other 11 lactococcal strains. In addition, the metabolic profile, antimicrobial susceptibility, and inhibitory activity of both protein-peptide extract (PPE) and exopolysaccharides (EPSs) against several foodborne pathogens were assessed in vitro. Furthermore, UTNCys6-1 was predicted to be a non-human pathogen that was unable to tolerate all tested antibiotics except gentamicin; metabolized several substrates; and lacks virulence factors (VFs), genes related to the production of biogenic amines, and acquired antibiotic resistance genes (ARGs). Overall, this study highlighted the potential of this strain for producing bioactive metabolites (PPE and EPSs) for agri-food and pharmaceutical industry use.