This paper describes Coriobacterium glomerans, a new genus and species of gram-positive anaerobic bacterium isolated from the intestinal tract of the red soldier bug (Pyrrhocoris apterus). Researchers collected 89 bacterial strains from bugs sampled in Bavaria, Germany. The organism forms long chains of pear-shaped cells and is found exclusively in the third bulbous portion of the insect's midgut, where it attaches to the intestinal epithelium. The bacterium is believed to function as a symbiont aiding in the insect's digestion of dry seeds. Biochemically, C. glomerans ferments glucose to produce acetic acid, lactic acid, ethanol, carbon dioxide, and hydrogen. The DNA G+C content is 60-61 mol%, and the cell wall peptidoglycan is of the Lys-Asp type. The authors distinguished this organism from related genera including Lactobacillus, Bifidobacterium, Eubacterium, and Lachnospira through differences in G+C content, fermentation product ratios, murein composition, and enzymatic characteristics. The type strain is C. glomerans PW2 (DSM 20642).

Key findings

• Coriobacterium glomerans is a new genus and species of gram-positive, obligately anaerobic bacterium isolated from 89 of 92 red soldier bugs sampled from Bavaria
• The organism forms chains exceeding 150 micrometers long and colonizes the third bulbous midgut portion of all insect life stages except eggs
• C. glomerans ferments glucose to produce acetic acid, lactic acid, ethanol, CO₂, and H₂, with a molar ratio of 1.16:1.00:0.95
• The bacterium has a DNA G+C content of 60-61 mol% and Lys-Asp type peptidoglycan, distinguishing it from Lactobacillus, Bifidobacterium, Eubacterium, and other related genera
• The organism is considered a symbiont of Pyrrhocoris apterus, likely aiding digestion of the insect's dry seed diet