Runella limosa sp. nov., isolated from activated sludge

Area of Science:

• Microbiology
• Environmental Science
• Bacteriology

Background:

• Enhanced biological phosphorus removal (EBPR) is crucial for wastewater treatment.
• Microbial communities in sequencing batch reactors (SBRs) play a key role in EBPR.
• Characterizing novel bacterial species aids in understanding complex microbial ecosystems.

Purpose of the Study:

• To isolate and characterize a novel bacterial strain from activated sludge involved in EBPR.
• To determine the taxonomic and phylogenetic placement of the novel isolate.
• To propose a new species within the genus Runella.

Main Methods:

• Isolation of strain EMB111(T) from activated sludge.
• Morphological, physiological, and biochemical characterization.
• Fatty acid analysis, polar lipid profiling, and quinone analysis.
• Genomic DNA G+C content determination.
• 16S rRNA gene sequence analysis for phylogenetic placement.

Main Results:

• Strain EMB111(T) is a strictly aerobic, non-motile, rod-shaped, Gram-negative bacterium.
• Optimal growth at 25-30°C and pH 7.5-8.0.
• Chemotaxonomic data revealed specific fatty acid profiles, phosphatidylglycerol as a major polar lipid, and menaquinone-7 as the major isoprenoid quinone.
• Phylogenetic analysis indicated closest relationship to Runella slithyformis with 94.8% 16S rRNA gene sequence similarity.
• Genomic G+C content was 42.7 mol%.

Conclusions:

• Strain EMB111(T) represents a novel species of the genus Runella.
• The proposed name for the novel species is Runella limosa sp. nov.
• This finding contributes to the understanding of bacterial diversity in wastewater treatment systems.