Enterococcus hailinensis sp. nov., Isolated from Traditional Chinese Pickle

Area of Science:

• Microbiology
• Food Science
• Bacteriology

Background:

• Enterococci are a group of bacteria commonly found in various environments, including fermented foods.
• Characterizing novel bacterial species is crucial for understanding microbial ecosystems and potential applications.

Purpose of the Study:

• To isolate and characterize novel enterococcal strains from traditional Chinese pickle ('Suan cai').
• To determine the taxonomic position of the isolates using a polyphasic approach.

Main Methods:

• Polyphasic characterization including 16S rRNA gene sequencing, whole genome sequencing, and phylogenetic analysis.
• Comparative analysis of Average Nucleotide Identity (ANI), digital DNA-DNA hybridization (dDDH), and Average Amino Acid Identity (AAI).
• Phenotypic characterization including acid production, biochemical tests, antibiotic resistance profiling, and growth condition analysis.

Main Results:

• Phylogenetic analyses placed the isolates (strains N48-2^T and N48-9.1) closest to Enterococcus hermanniensis.
• High sequence similarities in 16S rRNA, pheS, and rpoA genes were observed, but ANI, dDDH, and AAI values indicated distinct species.
• Significant phenotypic differences were identified, including acid production profiles, H₂S production, antibiotic resistance patterns, and tolerance to salt and temperature.

Conclusions:

• Strains N48-2^T and N48-9.1 represent a novel species within the genus Enterococcus.
• The proposed name for this new species is Enterococcus hailinensis sp. nov.
• This finding contributes to the knowledge of bacterial diversity in fermented food products.