Hydrolysis of xylans by enzyme systems from solid cultures of Trichoderma harzianum strains
Rev. bras. pesqui. méd. biol
; Braz. j. med. biol. res;32(8): 947-52, Aug. 1999.
Article
em En
| LILACS
| ID: lil-238962
Biblioteca responsável:
BR1.1
RESUMO
Xylanase activity was isolated from crude extracts of Trichoderma harzianum strains C and 4 grown at 28oC in a solid medium containing wheat bran as the carbon source. Enzyme activity was demonstrable in the permeate after ultrafiltration of the crude extracts using an Amicon system. The hydrolysis patterns of different xylans and paper pulps by xylanase activity ranged from xylose, xylobiose and xylotriose to higher xylooligosaccharides. A purified ß-xylosidase from the Trichoderma harzianum strain released xylose, xylobiose and xylotriose from seaweed, deacetylated, oat spelt and birchwood xylans. The purified enzyme was not active against acetylated xylan and catalyzed the hydrolysis of xylooligosaccharides, including xylotriose, xylotetraose and xylopentaose. However, the enzyme was not able to degrade xylohexaose. Xylanase pretreatment was effective for hardwood kraft pulp bleaching. Hardwood kraft pulp bleached in the XEOP sequence had its kappa number reduced from 13.2 to 8.9 and a viscosity of 20.45 cp. The efficiency of delignification was 33
Texto completo:
1
Coleções:
01-internacional
Base de dados:
LILACS
Assunto principal:
Trichoderma
/
Xilanos
/
Xilosidases
/
Técnicas de Cultura de Células
Idioma:
En
Revista:
Braz. j. med. biol. res
/
Rev. bras. pesqui. méd. biol
Assunto da revista:
BIOLOGIA
/
MEDICINA
Ano de publicação:
1999
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Brasil