Features of the biochemical adaptations of alkaliphilic fungi to exist in extreme environments could promote the production of active antibiotic compounds with the potential to control microorganisms, causing infections associated with health care. Thirty-eight alkaliphilic and alkalitolerant Emericellopsis strains (E. alkalina, E. cf. maritima, E. cf. terricola, Emericellopsis sp.) isolated from different saline soda soils and belonging to marine, terrestrial, and soda soil ecological clades were investigated for emericellipsin A (EmiA) biosynthesis, an antifungal peptaibol previously described for Emericellopsis alkalina. The analysis of the Emericellopsis sp. strains belonging to marine and terrestrial clades from chloride soils revealed another novel form with a mass of 1032.7 Da, defined by MALDI-TOF Ms/Ms spectrometers, as the EmiA lacked a hydroxyl (dEmiA). EmiA displayed strong inhibitory effects on cell proliferation and viability of HCT 116 cells in a dose- and time-dependent manners and induced apoptosis.

The adaptations that alkaliphilic microorganisms have developed due to their extreme habitats promote the production of active natural compounds with the potential to control microorganisms, causing infections associated with healthcare. The primary purpose of this study was to isolate and identify a hydrophobin, Sa-HFB1, from an alkaliphilic fungus, Sodiomyces alkalinus. A potential antifungal effect against pathogenic and opportunistic fungi strains was determined. The MICs of Sa-HFB1 against opportunistic and clinical fungi ranged from 1 to 8 µg/mL and confirmed its higher activity against both non- and clinical isolates. The highest level of antifungal activity (MIC 1 µg/mL) was demonstrated for the clinical isolate Cryptococcus neoformans 297 m. The hydrophobin Sa-HFB1 may be partly responsible for the reported antifungal activity of S. alkalinus, and may serve as a potential source of lead compounds, meaning that it can be developed as an antifungal drug candidate.

Peptaibols (Paib) are a class of biologically active peptides isolated from fungi and molds, which have attracted the attention of medicinal chemists due to their widely ranging pharmacological properties, including their antimicrobial activity. In the present study, we investigated the effects of various pH levels and cultivation conditions on peptaibol complex emericellipsins A-E (EmiA-E), produced by the alkaliphilic fungus Emericellopsis alkalina. Paib production has been studied in flasks and bioreactors for different pH values ranging from 7 to 11. The study of morphological features based on light and scanning electron microscopy has revealed differences between fungi grown at different pH values and cultivation conditions. Emericellipsins have been purified, sequenced, and identified by mass spectrometry. We have found that an alkaline pH of 10 could promote emericellipsins’ biosynthesis most effectively during stationary fermentation on the 14th day of cultivation.