RESUMO

Background: Mucor indicus is a dimorphic fungus used in the production of ethanol, oil, protein, and glucosamine. It can ferment different pentoses and hexoses; however, the yields of products highly depend on the nutrients and cultivation conditions. In this study, the effects of different morphologic forms, cultivation time and temperature, presence or absence of oxygen, carbon sources, and concentration of nitrogen source on the products of M. indicus were investigated. Results: The fungus with all morphologies produced high yields of ethanol, in the range of 0.32­0.43 g/g, on glucose. However, the fungus with filamentous morphology produced higher amounts of oil, protein, phosphate, and glucosamine together with ethanol, compared with other morphologies. A higher amount of oil (0.145 g/g biomass) was produced at 28°C, while the best temperature for protein and glucosamine production was 32 and 37°C, respectively. Although ethanol was produced at a higher yield (0.44 g/g) under anaerobic conditions compared with aerobic conditions (yield of 0.41 g/g), aerobic cultivation resulted in higher yields of protein (0.51 g/g biomass), glucosamine (0.16 g/g alkali insoluble material, AIM), and phosphate (0.11 g/g AIM). Conclusions: It is not possible to have the maximum amounts of the products simultaneously. The fermentation conditions and composition of culture media determine the product yields. Carbon source type and the addition of nitrogen source are among the most influencing factors on the product yields. Moreover, all measured products were made with higher yields in cultivation on glucose, except glucosamine, which was produced with higher yields on xylose.

Assuntos

Etanol/metabolismo , Mucor/metabolismo , Temperatura , Fatores de Tempo , Óleos/metabolismo , Carbono/metabolismo , Biomassa , Aerobiose , Meios de Cultura , Fermentação , Glucosamina/metabolismo , Glucose , Anaerobiose , Nitrogênio/metabolismo

RESUMO

Preservation methods for entomopathogenic fungi (EPF) require effective protocols to ensure uniform processes and to avoid alterations during storage. The aim of this study was to preserve Beauveria bassiana, Metarhizium acridum, M. anisopliae, M. rileyi, Isaria javanica, Hirsutella thompsonii, H. citriformis and Lecanicillium lecanii in mineral oil (MO), sterile water (SW), silica gel (SG), lyophilisation (L), ultracold-freezing at -70 °C, and cryopreservation at -196 °C. The viability and purity of the fungi were then verified: phenotypic characteristics were evaluated qualitatively at 6, 12 and 24 m. Genetic stability was tested by amplified fragment length polymorphisms (AFLP) analysis at 24 m. Of the eight species of EPF, three remained viable in SW, five in MO and L, six at -70 °C, seven in SG, and eight at -196 °C. No significant changes were observed in AFLP patterns at 24 m of storage. The most effective preservation methods for EPF were SG, L, -70 and -196 °C. Beauveria bassiana, M. acridum, M. anisopliae, M. rileyi and I. javanica remained stable with all methods, while the remaining species were less compatible. The optimisation of preservation methods for EPF facilitates the development of reliable protocols to ensure their inherent characteristics in culture collections.

Assuntos

Hypocreales/genética , Hypocreales/fisiologia , Preservação Biológica/métodos , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Instabilidade Genômica , Viabilidade Microbiana

RESUMO

Sporothrix schenckii is the etiological agent of the sporotrichosis in animals and humans being this mycosis of greatimportance in public health. Due to clinical, epidemiological and molecular differences described in other studies, this studyevaluated phenotypic and thermotolerance characteristics of 36 S. schenckii isolates from clinical cases of feline, canine andhuman sporotrichosis, four environmental isolates and two reference strains. Forty-two S. schenckii isolates from five townsof the south region of the Rio Grande do Sul, Brazil were utilized to phenotypic analyses, thermotolerance and conversion tothe yeast phase. Cultured isolates on lactrimel agar, Sabouraud dextrose agar added chloramphenicol and potato dextroseagar at 25 and 35oC showed differences in the colonies morphology and growth time (p=0,026) among reference strains and,clinical and environmental isolates. In the thermotolerance evaluation 26.2 % isolates were capable of growth at 41oC. Allisolates presented conversion to the yeast phase. Microscopic morphologies study showed statistical differences (p 0,01)among clinical isolates of felines and other species in relation to sessile pigmented and sympodial conidia. Our resultsdemonstrated morphological differences among S. schenckii clinical and environmental isolates of a same region and angreat probability of development of clinical forms disseminate

RESUMO

Sporothrix schenckii is the etiological agent of the sporotrichosis in animals and humans being this mycosis of greatimportance in public health. Due to clinical, epidemiological and molecular differences described in other studies, this studyevaluated phenotypic and thermotolerance characteristics of 36 S. schenckii isolates from clinical cases of feline, canine andhuman sporotrichosis, four environmental isolates and two reference strains. Forty-two S. schenckii isolates from five townsof the south region of the Rio Grande do Sul, Brazil were utilized to phenotypic analyses, thermotolerance and conversion tothe yeast phase. Cultured isolates on lactrimel agar, Sabouraud dextrose agar added chloramphenicol and potato dextroseagar at 25 and 35oC showed differences in the colonies morphology and growth time (p=0,026) among reference strains and,clinical and environmental isolates. In the thermotolerance evaluation 26.2 % isolates were capable of growth at 41oC. Allisolates presented conversion to the yeast phase. Microscopic morphologies study showed statistical differences (p 0,01)among clinical isolates of felines and other species in relation to sessile pigmented and sympodial conidia. Our resultsdemonstrated morphological differences among S. schenckii clinical and environmental isolates of a same region and angreat probability of development of clinical forms disseminate