Paracoccus binzhouensis sp. nov., isolated from activated sludge.

Area of Science:

• Microbiology
• Bacteriology
• Wastewater Microbiology

Background:

• Activated sludge from wastewater treatment plants harbors diverse microbial communities.
• The genus Paracoccus plays roles in various biogeochemical cycles.
• Characterization of novel bacterial isolates is crucial for understanding microbial diversity and function.

Purpose of the Study:

• To isolate and characterize a novel bacterial strain from activated sludge.
• To determine the taxonomic and phylogenetic placement of the novel strain.
• To evaluate the potential of the strain as a new species within the Paracoccus genus.

Main Methods:

• Isolation and cultivation of strain wg1^T from activated sludge.
• Physicochemical characterization including optimal growth conditions (temperature, pH, salinity).
• Chemotaxonomic analysis (quinones, fatty acids, polar lipids).
• Genomic analysis including 16S rRNA gene sequencing, genome size, G+C content, and average nucleotide identity (ANI).
• Phylogenetic analysis and DNA-DNA hybridization (dDDH) for taxonomic classification.

Main Results:

• Strain wg1^T is a gram-stain-negative, non-motile, rod-shaped bacterium.
• Optimal growth observed at 37°C, pH 8.0, and 1% salinity.
• 16S rRNA gene sequence analysis placed wg1^T within the genus Paracoccus, with highest similarity to P. communis (98.27%) and P. kondratievae (98.25%).
• Genomic data revealed a genome size of 4,834,448 bp with 67.67% G+C content.
• Low ANI and dDDH values (e.g., 45.30% with P. communis) supported its distinction from related species.
• The strain contains 12 predicted secondary metabolite clusters.

Conclusions:

• Strain wg1^T represents a novel species within the genus Paracoccus.
• Based on its distinct physiological, chemotaxonomic, and genomic characteristics, the name *Paracoccus binzhouensis* sp. nov. is proposed.
• The type strain is wg1^T (KCTC 72861^T = CCTCC AB 2019400^T).