Citromicrobium

Citromicrobium

Citromicrobium under a microscope

Citromicrobium is a genus of bacteria belonging to the family Rhodospirillaceae. These bacteria are known for their unique characteristics and play an important role in various ecological processes. The genus name Citromicrobium is derived from the Latin word citrus, meaning citrus fruit, and microbium, meaning microorganism, reflecting their ability to produce a yellow pigment and their microscopic nature.

Taxonomy

Citromicrobium was first described in 1999 by Imhoff et al. The genus currently consists of three species: Citromicrobium bathyomarinum, Citromicrobium luteolum, and Citromicrobium limosum. These species are distinguished based on their morphological, physiological, and genetic characteristics.

Morphology

Citromicrobium bacteria are Gram-negative, non-spore-forming, and spiral-shaped. They are typically 0.5-1.0 μm in width and 2-4 μm in length. These bacteria possess a single polar flagellum, which enables them to move in a corkscrew-like motion. Under a microscope, Citromicrobium cells appear as curved rods with a characteristic yellow color due to the presence of carotenoid pigments.

Habitat and Ecology

Citromicrobium bacteria are commonly found in marine and freshwater environments. They are often associated with sediments, where they play a crucial role in the carbon and sulfur cycles. These bacteria are capable of anaerobic respiration, utilizing various organic compounds as electron donors and sulfur compounds as electron acceptors. This metabolic versatility allows them to thrive in diverse habitats, including deep-sea sediments, salt marshes, and estuaries.

Importance

Citromicrobium bacteria have significant ecological importance due to their involvement in biogeochemical cycles. They contribute to the decomposition of organic matter, releasing essential nutrients back into the environment. Additionally, their ability to utilize sulfur compounds helps in the removal of toxic hydrogen sulfide from sediments, preventing its release into the water column.

Citromicrobium bathyomarinum

Citromicrobium bathyomarinum is a species within the genus Citromicrobium. It was first isolated from deep-sea sediments and has since been found in various marine environments. This species is characterized by its ability to grow under extreme conditions, such as high hydrostatic pressure and low temperatures. It plays a crucial role in the sulfur cycle of deep-sea sediments, contributing to the overall ecosystem functioning.

Citromicrobium luteolum

Citromicrobium luteolum is another species within the genus Citromicrobium. It is commonly found in freshwater environments, including lakes and rivers. This species is known for its yellow pigmentation, which gives it a distinctive appearance. Citromicrobium luteolum is involved in the degradation of organic matter and plays a vital role in nutrient cycling within freshwater ecosystems.

Citromicrobium limosum

Citromicrobium limosum is the third species within the genus Citromicrobium. It is often found in estuarine and salt marsh sediments. This species is capable of utilizing a wide range of organic compounds as energy sources, including fatty acids and alcohols. Citromicrobium limosum contributes to the overall carbon and sulfur cycling in these environments, playing a crucial role in maintaining the balance of nutrients.

See Also

• Rhodospirillaceae
• Microorganism
• Biogeochemical cycle
• Sulfur cycle