A rapidly growing hyaline mold began as a white colony but soon developed a black 'pepper' effect on the agar surface. What is the most likely identification?

The identification of the rapidly growing hyaline mold as Aspergillus niger is based on its distinctive growth characteristics. Aspergillus niger commonly starts as a white colony and can develop a characteristic black coloration over time, often described as a 'pepper' effect due to the appearance of its black conidia. This morphological change is indicative of its sporulation process, where the black spores become prominent as the culture matures.

Aspergillus niger is a widely studied fungus known for its rapid growth and ability to thrive in various environments, which aligns with the description of a rapidly growing mold. This species is often found in decaying organic matter and is recognized for its economic importance in industry, particularly in the production of enzymes and citric acid.

In contrast, the other options do not exhibit the same characteristics. For example, while Penicillium notatum is known for its blue-green pigmentation and typical penicillium morphology, it does not display the black pepper-like effect described. Paecilomyces species are generally characterized by their elongated conidiophores and produce spores with a different appearance. Scopulariopsis species tend to show a more consistent white to cream coloration and do not typically exhibit the rapid development of