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 objective of this work was to isolate bacteria from soil historically exposed to tebuconazole and to evaluate the biodegradation of this fungicide by them. Tebuconazole is a commonly used systemic fungicide of the triazol group, which inhibits the sterol C-14 alpha-demethylation of 24-methylenedihydrolanosterol, a precursor of ergosterol, a cell membrane component in fungi. Microorganisms were isolated by different methods of soil sampling and the screening of degrading bacteria was performed in bioreactors cultivations, with some isolates showing the ability to degrade up to 42.76 mg L(- 1) of tebuconazole (51% of the initial concentration). These strains were identified by standard biochemical procedures as being Enterobacter sakazakii and Serratia sp. These bacteria present some important characteristics for potential uses on environmental bioremediation, considering that tebucanozale is an extremely recalcitrant chemical.