Parengyodontium album

Parengyodontium album is a globally distributed fungal species known for breaking down plastics and items of historical importance. Discoveries in the early 21st century revealed its presence in marine ecosystems, colonizing and breaking down polyethylene, the most abundant plastic in oceans. Marine microbiologists from the Royal Netherlands Institute for Sea Research and collaborators from various international institutions found P. album, along with other marine microbes, living in thin biofilms on plastics scattered throughout the ocean. Though many types of bacteria have been shown to break down plastics, Parengyodontium album is only one of four species of marine fungi known to have this capability as of 2024.

Description
Parengyodontium album, also called Engyodontium album, typically grows in moist or waste environments and can be found on common materials like paper, jute, linen, and painted walls. It reproduces through dry, hydrophobic conditions, using a type of spore that allows the fungus to spread through the air and colonize new areas. The fungus forms white, fluffy colonies that can be observed as having clear, colorless undersides. Under a microscope, it displays narrow vegetative hyphae (the main growth structure of the fungus) along with fertile hyphae that branch out and bear conidiogenous cells (the specialized cells where spores are formed). The spores themselves are smooth, round, and transparent. This fungus, originally described as Tritirachium album (Limber, 1940), has undergone several taxonomic changes, initially included in a new genus created for species with verticillately branched conidiophores similar to those of Verticillium but differing in their final zigzag conidia-bearing portion. It was first isolated from a Penicillium colony in a marine biological laboratory, where it was considered a possible contaminant. This fungus is not only common in natural settings but has also been noted for its ability to thrive in human-made environments, and can become pathogenic, particularly in individuals with weakened immune systems.

Breakdown of ocean plastics
The degradation of polyethylene by Parengyodontium album is particularly notable because it occurs at a rate of about 0.05 percent per day under laboratory conditions, and this process is significantly influenced by sunlight. Researchers noted that the fungus only breaks down polyethylene that has been exposed to UV light, indicating that in natural settings, P. album likely affects plastics floating near the ocean surface. While the fungus converts most of the carbon from polyethylene into carbon dioxide, the environmental impact of this CO2 release is minimal, akin to the amount exhaled by humans during breathing.