Portal de Periódicos da CAPES

Artigo Produção Nacional Revisado por pares

BIBTEX RIS

Production and purification of alkaline xylanases

1999; Elsevier BV; Volume: 68; Issue: 1 Linguagem: Inglês

10.1016/s0960-8524(98)00079-0

1873-2976

Marta Cristina Teixeira Duarte, Edilberto Princi Portugal, Alexandre Nunes Ponezi, Mônica Andréa Bim, Cristiane Vanessa Tagliari, Telma Teixeira Franco,

Enzyme Catalysis and Immobilization

This work investigated more than 500 colonies with xylanolytic activity which were able to grow in a medium containing corn xylan as the only carbon source. Out of the 500 colonies, 22 microorganisms were also able to grow in birchwood xylan and were cellulase-free producers. The xylanase activity was studied at pH 10.0 and pH 5.0. It was observed that the three best producers of alkaline xylanase yielded enzyme levels in the range of 2.6 to 4.0 U/ml. Enzyme levels of 1.0 to 1.25 U/ml were achieved by four other microorganisms. Conversely, there were three microorganisms that produced a xylanase which was mostly active at pH 5.0. There was just one microorganism able to produce an enzyme active at pH 10.0. The alkaline xylanases from crude fermentation broth were extracted in aqueous two-phase systems (ATPS) composed of 16% polyethyleneglycol (PEG 6000) and 8% phosphate salt. A purification factor of 57 and a 41% yield of enzyme activity were achieved for the system containing 16% PEG 6000, 8% K2HPO4 and 12% NaCl.