Valeriano Antonio Corbellini

Cultivation of Desmodesmus subspicatus in a tubular photobioreactor for bioremediation and microalgae oil production

The microalgae Desmodesmus subspicatus (Chlorophyta) was cultivated in a tubular photobioreactor using effluent from the wastewater treatment plant of the University of Santa Cruz do Sul, Brazil to demonstrate the reactors operation. The algaes ability to remove nutrients from wastewater and the oleaginous potential of the algaes biomass were also evaluated. Total phosphorus and ammonia nitrogen were measured. The photobioreactor consisted of a system of three acrylic tubes, a reservoir, connections and a CO2 supply. The gas supply was semicontinuous with CO2 added from a cylinder. The cultures growth was estimated from cell numbers counted on a daily basis. Lipid content in the biomass was analysed using gas chromatography. A maximum cell density of 9.11×106 cells mL−1 and a dry weight of 234.00 mg L−1 were obtained during cultivation without CO2, and these values rose to 42.48×106 cells mL−1 and 1277.44 mg L−1, respectively, when CO2 was added to the cultivation. Differences in the quality of the effluent and the presence of CO2 did not result in different lipid profiles. The presence of palmitic acid and oleic acid was notable. The average extracted oil content was 18% and 12% for cultivation with and without the input of CO2, respectively.

Secretion of five extracellular enzymes by strains of chromoblastomycosis agents

The gelatinase, urease, lipase, phospholipase and DNase activities of 11 chromoblastomycosis agents constituted by strains of Fonsecaea pedrosoi, F. compacta, Phialophora verrucosa, Cladosporium carrionii, Cladophialophora bantiana and Exophiala jeanselmei were analyzed and compared. All strains presented urease, gelatinase and lipase activity. Phospholipase activity was detected only on five of six strains of F. pedrosoi. DNase activity was not detected on the strains studied. Our results indicate that only phospholipase production, induced by egg yolk substrate, was useful for the differentiation of the taxonomically related species studied, based on their enzymatic profile.

Study of different nitrogen sources on glucose uptake and production of melanin precursors and fungal mass of Fonsecaea pedrosoi cultured in tricyclazole

Abstract The influence of tricyclazole on the production of phenolic precursors, glucose uptake and production of fungal mass of Fonsecaea pedrosoi was assessed in the presence of phenylalanine, sodium nitrate and tryptophan. Photocolorimetry was used for the quantitation of glucose and total phenol, and the dry weight method for biomass. The glucose uptake with phenylalanine was 99.85×10 3 mg/ml; with tryptophan, 99.88×10 3 mg/ml and with sodium nitrate, 99.90×10 3 mg/ml. Production of biomass: with tryptophan, 2.7×10 −1 mg; with sodium nitrate, 3.0×10 −1 mg and with phenylalanine, 3.4×10 −1 mg. Tricyclazole induced higher phenol accumulation, lower glucose uptake, inhibition of melanin deposition on the cell and higher production and higher biomass production in relation to glucose uptake for all nitrogen sources tested under these conditions. A negative correlation between biomass production and glucose uptake was observed in the presence of secondary metabolism.

Potential Production of Biofuel from Microalgae Biomass Produced in Wastewater

Microalgae are the principal primary producers of oxygen in the world and exhibit enor‐ mous potential for biotechnological industries. Microalgae cultivation is an efficient option for wastewater bioremediation, and these microorganisms are particularly efficient at recov‐ ering high levels of nitrogen, inorganic phosphorus, and heavy metals from effluent. Fur‐ thermore, microalgae are responsible for the reduction of CO2 from gaseous effluent and from the atmosphere. In general, the microalgae biomass can be used for the production of pigments, lipids, foods, and renewable energy [1].

In vitro antifungal activity of 2-(2′-hydroxy-5′-aminophenyl)benzoxazole in Candida spp. strains

The development of azole antifungals has allowed for the treatment of several fungal infections. However, the use of these compounds is restricted because of their hepatotoxicity or because they need to be administered together with other drugs in order to prevent resistance to monotherapy. Benzoxazole derivatives are among the most thriving molecular prototypes for the development of antifungal agents. 2‐(2′‐hydroxyphenyl) benzoxazoles are versatile molecules that emit fluorescence and have antibacterial, antiviral and antifungal properties. 2‐(2′‐hydroxy‐5′‐aminophenyl) benzoxazole (HAMBO) was tested against Candida yeast. The inhibition provided by HAMBO was lower than that of fluconazole, showing low antifungal activity against Candida spp., but equivalent to that of benzoxazoles tested in similar studies. HAMBO showed fungistatic activity against all analysed strains. This class of novel benzoxazole compounds may be used as template to produce better antifungal drugs.

By-products from the biodiesel chain as a substrate to citric acid production by solid-state fermentation

In this study, we propose the use of tung cake for the production of organic acids, with an emphasis on citric acid by solid-state fermentation. We evaluated the conditions of production and the by-products from the biodiesel chain as raw materials involved in this bioprocess. First, we standardized the conditions of solid-state fermentation in tung cake with and without residual fat and with different concentrations of glycerine using the fungus Aspergillus niger. The solid-state fermentation process was monitored for 7 days considering the biomass growth and pH level. Citric acid production was determined by high-performance liquid chromatography. Fungal development was better in the crude tung cake, consisting of 20% glycerine. The highest citric acid yield was 350 g kg−1 of biomass. Therefore, the solid-state fermentation of the tung cake with glycerine led to citric acid production using the Aspergillus niger fungus.

Environmental pathways and human exposure to manganese in southern Brazil

The study of environmental pathways and human exposure to Manganese (Mn) in Southern Brazil was performed using two steps. The first step consisted of taking water samples from the surface of the Pardinho River. The average results from this technique showed a significant increase of pollutants, including increased levels of Mn, above the environmentally acceptable standard recommended by the Brazilian National Environment Council. Additionally, 64 soil samples were taken from areas with and without agricultural activity. Many results were above the mean crust and did not indicate significant differences of Mn levels between the sampled areas. For the second step, 12 families were selected and assessed for exposure to Mn in a region with high levels of Mn in the soil. Most of the analyzed foods contained amounts of Mn above the reference values, indicating that food can be an important source of exposure. The Mn content from the hair of most subjects studied was also high compared to reference values from non-exposed populations. Although the contamination appeared to come from a natural origin, the results found in the present study showed that the Mn levels present in the Pardinho River Basin are a relevant public health issue.

APPLICATION OF 6-NITROCOUMARIN AS A SUBSTRATE FOR THE FLUORESCENT DETECTION OF NITROREDUCTASE ACTIVITY IN Sporothrix schenckii

Introduction Sporothrix schenckii is a thermal dimorphic pathogenic fungus causing a subcutaneous mycosis, sporotrichosis. Nitrocoumarin represents a fluorogenic substrate class where the microbial nitroreductase activity produces several derivatives, already used in several other enzyme assays. The objective of this study was the analysis of 6-nitrocoumarin (6-NC) as a substrate to study the nitroreductase activity in Sporothrix schenckii. Methods Thirty-five samples of S. schenckii were cultivated for seven, 14 and 21 days at 35 °C in a microculture containing 6-nitrocoumarin or 6-aminocoumarin (6-AC) dissolved in dimethyl sulfoxide or dimethyl sulfoxide as a negative control, for posterior examination under an epifluorescence microscope. The organic layer of the seven, 14 and 21-day cultures was analyzed by means of direct illumination with 365 nm UV light and by means of elution on G silica gel plate with hexane:ethyl acetate 1:4 unveiled with UV light. Results All of the strains showed the presence of 6-AC (yellow fluorescence) and 6-hydroxylaminocoumarin (blue fluorescence) in thin layer chromatography, which explains the green fluorescence observed in the fungus structure. Conclusion The nitroreductase activity is widely distributed in the S. schenckii complex and 6-NC is a fluorogenic substrate of easy access and applicability for the nitroreductase activity detection.

Melanin: Quantification and protection against oxidative stress in chromoblastomycosis agents

Chromoblastomycosis (CBM) is a chronic cutaneous and subcutaneous infection caused by melanized fungal species. We quantified the extractable melanin of 77 strains of CBM agents distributed within five genera. Moreover, resistance to oxidative stress was evaluated in strains exposed or not to the melanin inhibitor tricyclazole. The median percentage of melanin mass extracted from dry fungal mass varied from 0.69 (Rhinocladiella similis) to 3.81 (Phialophora americana). Inhibition of melanin synthesis decreased survival rates to hydrogen peroxide. Together, these data highlight the importance of melanin in CBM agents.

Differentiation of Candida albicans, Candida glabrata, and Candida krusei by FT-IR and chemometrics by CHROMagar™ Candida

Pathogenic Candida species are detected in clinical infections. CHROMagar™ is a phenotypical method used to identify Candida species, although it has limitations, which indicates the need for more sensitive and specific techniques. Infrared Spectroscopy (FT-IR) is an analytical vibrational technique used to identify patterns of metabolic fingerprint of biological matrixes, particularly whole microbial cell systems as Candida sp. in association of classificatory chemometrics algorithms. On the other hand, Soft Independent Modeling by Class Analogy (SIMCA) is one of the typical algorithms still little employed in microbiological classification. This study demonstrates the applicability of the FT-IR-technique by specular reflectance associated with SIMCA to discriminate Candida species isolated from vaginal discharges and grown on CHROMagar™. The differences in spectra of C. albicans, C. glabrata and C. krusei were suitable for use in the discrimination of these species, which was observed by PCA. Then, a SIMCA model was constructed with standard samples of three species and using the spectral region of 1792-1561cm-1. All samples (n=48) were properly classified based on the chromogenic method using CHROMagar™ Candida. In total, 93.4% (n=45) of the samples were correctly and unambiguously classified (Class I). Two samples of C. albicans were classified correctly, though these could have been C. glabrata (Class II). Also, one C. glabrata sample could have been classified as C. krusei (Class II). Concerning these three samples, one triplicate of each was included in Class II and two in Class I. Therefore, FT-IR associated with SIMCA can be used to identify samples of C. albicans, C. glabrata, and C. krusei grown in CHROMagar™ Candida aiming to improve clinical applications of this technique.