Rhizopus

Rhizopus is a genus of filamentous fungi in the family Mucoraceae, order Mucorales. Members are widespread in nature, commonly found in soil, plant debris, and decaying organic matter, and they frequently appear as food spoilage agents on bread, fruit, and other carbohydrate-rich substrates. Several species are notable for their rapid growth and characteristic cottony, often black-spored colonies.

Morphology and reproduction: Rhizopus species typically have coenocytic (aseptate) hyphae and form rhizoids at the base of their growing point, with stolons connecting upright sporangiophores. Asexual reproduction occurs through sporangia that enclose spores (sporangiospores) at the ends of sporangiophores. Sexual reproduction involves the fusion of compatible mating strains to produce thick-walled zygospores within specialized structures called zygosporangia.

Ecology and uses: In the environment, Rhizopus species are saprotrophs that play a role in the decay of organic matter. Some species are also used in fermentation, most notably Rhizopus oligosporus and related strains in the production of tempeh from soybeans. Other species can be plant pathogens or opportunistic organisms in clinical settings.

Medical significance: Rhizopus species are among the fungi that can cause mucormycosis, a serious opportunistic infection that primarily affects immunocompromised individuals and can involve the sinuses, brain, or lungs. Treatment requires prompt medical attention, often combining surgical intervention with antifungal therapy such as amphotericin B.

Notable species: Rhizopus stolonifer (bread mold) is widely recognized for spoiling bakery products, while Rhizopus oryzae is commonly associated with food fermentation processes and clinical relevance in humans.