Pellet formation of zygomycetes and immobilization of yeast.

Pelleted growth provides many advantages for filamentous fungi, including decreased broth viscosity, improved aeration, stirring, and heat transfer. Thus, the factors influencing the probability of pellet formation of Rhizopus sp. in a defined medium was investigated using a multifactorial experimental design. Temperature, agitation intensity, Ca(2+)-concentration, pH, and solid cellulose particles, each had a significant effect on pelletization. Tween 80, spore concentration, and liquid volume were not found to have a significant effect. All of the effects were additive; no interactions were significant. The results were used to create a simple defined medium inducing pelletization, which was used for immobilization of a flocculating strain of Saccharomyces cerevisiae in the zygomycetes pellets. A flor-forming S. cerevisiae strain was also immobilized, while a non-flocculating strain colonized the pellets but was not immobilized. No adverse effects were detected as a result of the close proximity between the filamentous fungus and the yeast, which potentially allows for co-fermentation with S. cerevisiae immobilized in pellets of zygomycetes.

Identification and susceptibility of Rhizomucor spp. isolated from patients with cutaneous zygomycosis in China.

Zygomycosis is a relatively uncommon mycosis with a morbidity that is increasing worldwide. Cutaneous zygomycosis, one of the clinical manifestations of the disease, has also emerged in recent decades. The major reported etiologic agents in China include Rhizomucor spp., Rhizopus spp., Mucor spp., and Lichtheimia spp. (formerly Absidia spp.). This study examined 11 clinical isolates of Rhizomucor that belong to three species (R. variabilis, R. regularior, and R. chlamydosporus). They were identified by both morphological and molecular methods and were found to have a high degree of correlation. In vitro susceptibility of the Rhizomucor isolates to seven antifungal drugs (amphotericin B, itraconazole, terbinafine, voriconazole, fluconazole, flucytosine, and micafungin) were tested, which resulted in amphotericin B being found to be the most active agent against all species evaluated in this study. The investigation also reviewed case reports of cutaneous zygomycosis in China.