Genomic and metabonomic insights into the lignin-degrading potential of a novel halophilic bacterial strain Salinicoccus sp. HZC-1.

Lignin-derived aromatic compounds have significant potential for multiple industrial applications, and elucidating the processes for bacterial lignin degradation processes can facilitate the utilization of plant biomass. A lignin-degrading bacterial strain, designated HZC-1, was newly isolated from saline-alkali soil and exhibited robust growth in 1-18% (w/v) NaCl and across a pH range of 5.0-11.0. The isolate showed the highest 16S rRNA gene sequence similarity (≤ 97.7%) to known Salinicoccus species. Furthermore, average nucleotide identity (≤ 82.34) and digital DNA-DNA hybridization (≤ 52.9%) analyses supported its classification as a potentially novel species within the genus Salinicoccus. Genomic annotation indicated that strain HZC-1 adapted to saline-alkali environments via multiple mechanisms such as Na⁺/H⁺ antiporter and glycine betaine transport systems. By combining genomic and untargeted metabolomic data, it can be inferred that this strain was capable of metabolizing lignin derivatives through non-classical pathways involving enzymes such as β-glucosidase, aromatic cyclohydroxyl dioxygenase and those associated with naphthalene degradation. These findings suggest the potential lignin-degrading capacity of Salinicoccus sp. HZC-1 under saline-alkali conditions, presenting a potentially novel bacterial taxon for waste lignin valorization and bioremediation of aromatic pollutants.