Introduction:In vitro bioassays were performed to access the larvicidal activity of crude extracts from the endophytic fungus Pestalotiopsis virgulata (Melanconiales, Amphisphaeriaceae) and the saprophytic fungus Pycnoporus sanguineus (Basidiomycetes, Polyporaceae) against the mosquitoes Aedes aegypti and Anopheles nuneztovari. Methods: The extracts were tested at concentrations of 100, 200, 300, 400 and 500ppm. Ethyl acetate mycelia (EAM) extracts and liquid culture media (LCM) from Pe. virgulata and Py. sanguineus were tested against third instar larvae of Ae. aegypti and An. nuneztovari. Results: The larvicidal activity of the EAM extracts from Pe. virgulata against Ae. aegypti had an LC 50 =101.8ppm, and the extract from the basidiomycete fungus Py. sanguineus had an LC 50 =156.8ppm against the Ae. aegypti larvae. The Pe. virgulata extract had an LC 50 =16.3ppm against the An. nuneztovari larvae, and the Py. sanguineus extract had an LC 50 =87.2ppm against these larvae. Conclusions: These results highlight the larvicidal effect of EAM extracts from the endophyte Pe. virgulata against the two larval mosquitoes tested. Thus, Pe. virgulata and Py. sanguineus have the potential for the production of bioactive substances against larvae of these two tropical disease vectors, with An. nuneztovari being more susceptible to these extracts.
The stress imposed by ethanol to Saccharomyces cerevisiae cells are one of the most challenging limiting factors in industrial fuel ethanol production. Consequently, the toxicity and tolerance to high ethanol concentrations has been the subject of extensive research, allowing the identification of several genes important for increasing the tolerance to this stress factor. However, most studies were performed with well-characterized laboratory strains, and how the results obtained with these strains work in industrial strains remains unknown. In the present work, we have tested three different strategies known to increase ethanol tolerance by laboratory strains in an industrial fuel–ethanol producing strain: the overexpression of the TRP1 or MSN2 genes, or the overexpression of a truncated version of the MSN2 gene. Our results show that the industrial CAT-1 strain tolerates up to 14% ethanol, and indeed the three strategies increased its tolerance to ethanol. When these strains were subjected to fermentations with high sugar content and cell recycle, simulating the industrial conditions used in Brazilian distilleries, only the strain with overexpression of the truncated MSN2 gene showed improved fermentation performance, allowing the production of 16% ethanol from 33% of total reducing sugars present in sugarcane molasses. Our results highlight the importance of testing genetic modifications in industrial yeast strains under industrial conditions in order to improve the production of industrial fuel ethanol by S. cerevisiae.
Introduction:In this study, we used dichloromethane (DCM) and methanol (MeOH) extracts of the Zingiber zerumbet rhizome to evaluate brine shrimp lethality and larvicidal activity on Aedes aegypti and Anopheles nuneztovari mosquitoes. Methods: Bioassays were performed by exposing third-instar larvae of each mosquito species to the DCM or MeOH extracts. Results: Probit analysis with DCM and MeOH extracts demonstrated effi cient larvicidal activity against A. aegypti and A. nuneztovari larvae. Conclusions: The DCM and MeOH extracts showed higher activity against A. nuneztovari larvae than against A. aegypti larvae, suggesting that the extracts have species-specifi c activity.
The stress imposed by ethanol to Saccharomyces cerevisiae cells are one of the most challenging limiting factors in industrial fuel-ethanol production. Consequently, the toxicity and tolerance to high ethanol concentrations has been the subject of extensive research, allowing the identification of several genes important for increasing the tolerance to this stress factor. However, most studies were performed with well characterized laboratory strains, and how the results obtained with these strains work in industrial strains remains unknown. In the present work we have tested three different strategies known to increase ethanol tolerance by laboratory strains in an industrial fuel-ethanol producing strain: overexpression of the TRP1 or MSN2 genes, or overexpression of a truncated version of the MSN2 gene. Our results show that the industrial CAT-1 strain tolerates up to 14% ethanol, and indeed the three strategies increased its tolerance to ethanol. When these strains were subjected to fermentations with high sugar content and cell-recycle, simulating the industrial conditions used in Brazilian distilleries, only the strain with overexpression of the truncated MSN2 gene showed improved fermentation performance, allowing the production of 16% ethanol from 33% of total reducing sugars present in sugarcane molasses. Our results highlight the importance of testing genetic modifications in industrial yeast strains under industrial conditions in order to improve the production of industrial fuel ethanol by S. cerevisiae.
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<p>The tropical fruit cupuassu comes from <italic>Theobroma grandiflorum</italic> (SCHUM), a close relative of cocoa. Cupuassu has a rich yet delicate flavour profile with notes of chocolate, pineapple, passion fruit and other fruits. Here, we produced a cupuassu-fruit wine using a Saccharomyces cerevisiae inoculum (and univariate analysis to determine conditions for optimum ethanol production) and then fermented this wine to produce a delicate and unique cupuassu vinegar using acid-acid bacteria. The cupuassu wine was produced by fermentation of juice chaptalized with sucrose, with a final ethanol concentration of 10% (v/v). Acetic-acid fermentations were carried out in both a bubble-column reactor and a mechanically non-aerated reactor (high-surface reactor), producing final concentrations of 4.5 and 3.3% (w/v) acetic acid, respectively. The ethanol- and acetic-acid yields obtained were comparable to those of other fruit wines and fruit vinegars. The cupuassu vinegar retained the rich flavor profile of the cupuassu. We believe that the production of flavorsome products from local plants can have benefits for conservation by promoting ecologically sustainable agriculture and may contribute to cultural identity of Amazon people.</p>
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In Brazil, sucrose-rich broths (cane juice and/or molasses) are used to produce billions of liters of both fuel ethanol and cachaça per year using selected Saccharomyces cerevisiae industrial strains. Aiming to improve this disaccharide fermentation, we have first determined the genetic characteristics, by array comparative genomic hybridization, of a group of 8 fuel ethanol and 5 cachaça industrial yeasts that tend to dominate the fermentors during the production season. The widespread presence of SUC genes encoding invertase at multiple telomeres has been shown to be a common feature of both baker’s and distillers’ yeast strains and is postulated to be an adaptation to sucrose-rich broths. Our results show that only two strains (one fuel ethanol and one cachaça yeast) have amplification of the SUC genes, with high invertase activity. The other industrial yeast strains had a single SUC locus (SUC2) in their genome, with different patterns of invertase activity. These results indicate that invertase activity probably does not limit sucrose fermentation during fuel ethanol and cachaça production by these industrial strains. Using this knowledge, we changed the mode of sucrose metabolism of an industrial strain by avoiding extracellular invertase activity, overexpressing the intracellular invertase, and increasing its transport through the AGT1 permease. This approach allowed higher ethanol production from sucrose by the modified industrial yeast when compared to its parental strain.
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