Micellum

Micellum is a genus of small, filamentous algae that are commonly found in freshwater habitats such as streams, ponds and wet soil. The organisms are typically microscopic, with slender filaments that grow in loose strands or loosely bundled mats. Each filament is composed of a single row of cells that are relatively short and cylindrical, often tapering towards the tips. The cells possess a central vacuole and contain chloroplasts arranged around the periphery, enabling efficient photosynthesis in low‑light environments.

Taxonomically, Micellum has been placed in the family Micelleraceae within the order Selenococcales. The genus was first described in the early 19th century by botanist Franz von Bentham, and subsequent revisions have revised its boundaries based on morphological and molecular criteria. Currently, about ten species are recognized, including Micellum simplex, Micellum tersum and Micellum boreale. Recent DNA sequencing of ribosomal RNA genes has confirmed that Micellum forms a monophyletic group distinct from closely related genera such as Liebermannia and Pithophora.

Ecologically, Micellum species are important primary producers in the microhabitats they colonize. Their filaments provide a substrate for bacteria and protozoa, and they contribute to the carbon and nutrient cycles within freshwater systems. Some species have been used as bioindicators of ecological health, as their presence or absence can reflect water quality and the impact of anthropogenic pollution.

In addition to their ecological role, Micellum species have attracted interest for their potential use in biotechnological applications. Preliminary studies suggest that these algae may accumulate carotenoids and other secondary metabolites that could be harnessed for nutraceuticals and pharmaceuticals. However, detailed investigations into their biochemical pathways and optimal cultivation conditions are still necessary.

Overall, Micellum represents a small but ecologically significant group of freshwater algae, with a well‑defined taxonomic framework and promising potential for future research.