Clostridium zeae sp. nov., isolated from corn silage

Area of Science:

• Microbiology
• Bacteriology
• Genomics

Background:

• Isolation of novel bacterial strains from silage is crucial for understanding microbial ecosystems.
• The genus Clostridium encompasses diverse anaerobic bacteria with significant ecological and industrial roles.

Purpose of the Study:

• To characterize a newly isolated bacterial strain from corn silage.
• To determine the taxonomic position of strain CSC2^T using polyphasic methods.

Main Methods:

• Isolation and cultivation of anaerobic bacteria.
• Gram staining, catalase test, and endospore formation assessment.
• Cellular fatty acid analysis and polar lipid profiling.
• 16S rRNA gene sequencing and phylogenetic analysis.
• Whole genome analysis for G+C content determination.
• Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) calculations.

Main Results:

• Strain CSC2^T is a rod-shaped, Gram-negative, strictly anaerobic, catalase-negative, endospore-forming bacterium.
• Optimal growth occurred between 15-40°C, pH 5.0-7.7, and up to 0.5% NaCl.
• Phylogenetic analysis placed strain CSC2^T within the genus Clostridium, closely related to Clostridium polyendosporum and Clostridium fallax.
• Genomic analysis revealed a G+C content of 31.1 mol%, with ANI and dDDH values below established thresholds for species delineation.
• Distinct genotypic, phenotypic, and chemotaxonomic features differentiate strain CSC2^T from related species.

Conclusions:

• Strain CSC2^T represents a novel species of the genus Clostridium, named Clostridium zeae sp. nov.
• The type strain is CSC2^T (=MAFF212476^T=JCM 33766^T=DSM 111242^T).
• This finding expands the known diversity within the Clostridium genus and contributes to silage microbiology.