RESUMEN
The aims of this work were to improve cell tolerance towards high concentrations of furfural and 5-hydroxymethylfurfural (HMF) of an osmotolerant strain of Wickerhamomyces anomalus by means of evolutionary engineering, and to determine its ethanol production under stress conditions. Cells were grown in the presence of furfural, HMF, either isolated or in combination, and under high osmotic pressure conditions. The most toxic condition for the parental strain was the combination of both furans, under which it was unable to grow and to produce ethanol. However, the tolerant adapted strain achieved a yield of ethanol of 0.43 g g-1glucose in the presence of furfural and HMF, showing an alcohol dehydrogenase activity of 0.68 mU mg protein-1. For this strain, osmotic pressure, did not affect its growth rate. These results suggest that W. anomalus WA-HF5.5strain shows potential to be used in second-generation ethanol production systems.
Asunto(s)
Furaldehído , Saccharomycetales , Etanol , Furaldehído/análogos & derivados , Presión OsmóticaRESUMEN
The isolation of vancomycin resistant enterococci (VRE) in Brazil has rapidly increased, following the world wide tendency. We report in the present study the first isolation of vancomycin resistant Enterococcus faecalis (VRE) in the Northeast of Brazil. The four VRE isolates were characterized for antimicrobial susceptibility, genotypic typing by macro restriction of chromosomal DNA followed by pulsed-field gel electrophoresis and for characterization of the Tn1546-like element and plasmid contents. The isolates showed resistance to multiple antibiotics and a single genotype profile, suggesting the dissemination of a single clone among the patients. Tn1546 associated to genetic elements as plasmids shows the importance of infection control measures to avoid the spreading of glycopeptide resistance by conjugative transfer of VanA elements.