Fungal communities in pressmud composting harbour beneficial and detrimental fungi for human welfare

Abstract

Pressmud is a substrate derived from sugarcane juice filtrate, and around 26-40 kg of this residue are produced per ton of sugarcane. It is mainly used as fertilizer in crops, and its application in the field is often made without any prior treatment, but, in this research, it was studied for the risk this practice poses for human health. This research was stimulated by previous results indicating the presence of opportunistic pathogens in residues used in various composting systems and the extensive use of fresh pressmud in agriculture. Here, It was assessed the fungal diversity present in both fresh and composting pressmud using 454 pyrosequencing. In addition, heat-tolerant fungi were isolated and surveyed for their enzymatic repertoire of biomass-degrading enzymes (cellulase, xylanase, laccase and polygalacturonase). A wide range of opportunistic pathogens was found among the most abundant taxa in the fresh pressmud, such as Lomentospora prolificans (43.13 %), Trichosporon sp. (10.07 %), Candida tropicalis (7.91 %), and Hormographiella aspergillata (8.19 %). This indicates that fresh pressmud might be a putative source of human pathogenic fungi, presenting a potential threat to human health if applied as fertilizer without any treatment. With regard to the heat-tolerant fungi found in this substrate, all the 110 isolates screened were able to produce at least one of the tested enzymes. The pressmud composting process not only effectively reduces the load of pathogenic fungi, but also creates an interesting environment for fungi able to produce thermostable hydrolytic and oxidative enzymes with biotechnological applications.

Population genomics of the pathogenic yeast Candida tropicalis identifies hybrid isolates in environmental samples

“…Like many opportunistic pathogens of humans, the natural habitat of C. tropicalis is unclear. Although C. tropicalis is well-adapted to humans, isolates are also commonly isolated from a variety of sources, including soil, sand, animal feces, by-products of industrial food production and the surface of fruits [51][52][53][54][55][56]. C. tropicalis is also a component of the human oral and gastrointestinal mycobiome [57,58] and has been isolated from human skin [59] and the…”

Hormographiella aspergillata: an emerging basidiomycete in the clinical setting? A case report and literature review

“…Hormographiella aspergillata is an environmental filamentous basidiomycete found in numerous substrates including soils, leaves, pressmud compost and in the air [ 3 , 4 ]. It is the anamorph form of Coprinopsis cinerea (formerly Coprinus cinereus ), which commonly grows on horse dung.…”

“…Hormographiella aspergillata is a filamentous basidiomycete growing on horse dung. It was found in numerous environmental substrates and first reported as a human pathogen in 1971 [ 2 – 4 ]. Since, a few infections were reported all over the world with various clinical outcomes, essentially pulmonary but also disseminated or located to the eye or the skin [ 2 , 5 – 22 ].…”

Population genomics of the pathogenic yeast Candida tropicalis identifies hybrid isolates in environmental samples

“…Like many opportunistic pathogens of humans, the natural habitat of C. tropicalis is unclear. Although C. tropicalis is well-adapted to humans, isolates are also commonly isolated from a variety of sources, including soil, sand, animal feces, byproducts of industrial food production and the surface of fruits [70][71][72][73][74][75]. C. tropicalis is also a component of the human oral and gastrointestinal mycobiome [76,77] and has been isolated from human skin [78] and the gastrointestinal tracts of mice [79].…”