PROIMI   05436
PLANTA PILOTO DE PROCESOS INDUSTRIALES MICROBIOLOGICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
CHARACTERIZATION OF EXTRACELLULAR XYLANASES FROM Paenibacillus sp. AR247
Autor/es:
SORAIRE, PABLO MARTÍN; DI MARCO, ENZO; ETCHEGORRY, DANIEL ; PEROTTI, NORA INÉS; MARTINEZ, M. ALEJANDRA
Lugar:
Rosario
Reunión:
Congreso; IX Congreso Argentino de Microbiología General SAMIGE; 2013
Institución organizadora:
SAMIGE (Sociedad Argentina de MIcrobiología)
Resumen:
Microbial biocatalysts, both from bacteria and yeast, have been developed for the conversion ofglucose derived from cellulose and pentoses derived from hemicellulose to ethanol. Current research efforts are directed to improve the pretreatment processes to maximize the release of fermentable pentoses as well as glucose in an attempt to maximize the yields of bioethanol from lignocellulosic substrates. Hemicellulose represents from 20% to 30% of lignocellulosic biomass, being the xylan the dominant polymer of hemicellulose. Its complete enzymatic hydrolysis requires the combined action of several xylanases.The aim of this work was to achieve a preliminar characterization of the extracellular xylanases from Paenibacillus sp. AR247, after its production in a culture medium previously improved in ourlaboratory. The zymographic analyses revealed a profile of at least four bands with xylanolytic activity in the range of 50 to 120 kDa. These results were analyzed by means of the whole genome sequence of Paenibacillus sp. AR247 in order to detect their codifying sequences.Our studies included assays to determine the optimum temperature and pH of the xylanolytic activity of crude extracts, as well as the stability against temperature, EDTA, Tween 80 and SDS. In all cases, the enzymatic activity was quantified by determining reducing sugars released with the3,5-Dinitrosalicylic acid (DNS) reagent.The results obtained showed that the enzymatic activity on xylan of the crude extract had an optimum pH at 6, while the optimum temperature was 50°C. Regarding thermal stability, we observed that more than 80% of enzymatic activity was retained after incubation for 1 h in the range of 0°C to 50°C.However, the crude extract was inactive after thermal pretreatments at 60°C and 70°C. Finally, thexylanases evaluated here were stable in presence of EDTA, where they retained almost 70% activity, while in the presence of Tween 80 and SDS, the enzymatic activity retained was of 68% and 58%, respectively.