Alkaline xylanases produced by four different strains of Bacillus pumilus were characterized. The optimal pH and temperature were pH 9.0 and 60ºC for strain 13 a , and pH 8.0 and 55ºC for strains 5 2 , 5 14 , and 4 a. Under these conditions the following activities were found after 10 min in the presence of 1% xylan (birchwood): 328 U.ml-1 , 131 U.ml-1 , 90 U.ml-1 , and 167 U.ml-1 , respectively, for the four strains. The enzymes were stable at 40ºC, with 40% of the xylanase activity remaining after 2 hours for the enzymes of strain 5 2 and 60% for the other three strains. Stability at 50ºC was improved by addition of glycerol. Taking into account the conditions under which kraft pulps are bleached during the manufacture of paper, xylanases from B. pumilus exhibit favorable potential for application to bleaching in the paper making process.
RESUMOConduziu-se um experimento para testar a compatibilidade dos fungicidas capta, PCNB e tira com a inoculação de sementes de amendoim, cujo tratamento se efetuou simultaneamente com a inoculação ou dez dias antes desta. No momento da inoculação e quatro horas após, fez-se uma contagem de Rhizobium nas sementes, pelo método da diluição e inoculação de gotas em placas, mantendo-se um controle sem aplicação de fungicida. Para se estudar o efeito dos tratamentos na nodulação e fixação, plantaram-se as sementes em solo esterilizado, avaliando-se a nodulação e o teor de ureídeos nas folhas. Somente o capta aplicado simultaneamente ã inoculação foi prejudicial à sobrevivência bacteriana nas sementes. De maneira geral, a aplicação dos fungicidas simultaneamente à inoculação mostrou-se prejudicial em relação à antecipada.Termos de indexação: Rbizobium-fungicida, compatibilidade; amendoim, Arachis hypogaea L.
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