title: Xylan-hydrolyzing enzyme system from Bacillus pumilus CBMAI 0008 and its effects on Eucalyptus grandis kraft pulp for pulp bleaching improvement.
abstract: The extracellular productions of beta-xylanase, beta-xylosidase, beta-glucosidase, beta-mannanase, arabinosidase, alpha-glucuronidase, alpha-galactosidase and Fpase from Bacillus pumilus CBMAI 0008 were investigated with three different xylan sources as substrate. The enzymatic profiles on birchwood, Eucalyptus grandis and oat were studied at alkaline and acidic pH conditions. B. pumilus CBMAI 0008 grown on the three carbon sources produced mainly beta-xylanase. At pH 10, the levels of xylanase were 328, 160 and 136 U/ml, for birch, oat and E. grandis, respectively. beta-Mannanase production was induced on E. grandis (5 U/ml) and arabinofuranosidase on oat (5 U/ml). Although small quantities of alpha-glucuronidase had been produced at pH 10, activity at pH 4.8 was 1.5 U/ml, higher than observed for Aspergillus sp. in literature reports. Preliminary assays carried out on E. grandis kraft pulp from an industrial paper mill (RIPASA S.A. Celulose e Papel, Limeira, SP, Brazil) showed a reduction of 0.3% of chlorine use in the pulp treated with the enzymes, resulting in increased brightness, compared to conventional bleaching. The enzymes were more efficient if applied before the initial bleaching sequence, in a non-pre-oxygenated pulp.
authors.affiliation: Center for Chemical, Biological and Agricultural Research, CPQBA/UNICAMP, P.O. Box 6171, CEP, SP 13083-970, Campinas, Brazil. mduarte@cpqba.uniamp.br
authors.forename: Marta C Teixeira
authors.initials: MC
authors.lastname: Duarte
authors.forename: Elizete Cristina
authors.initials: EC
authors.lastname: da Silva
authors.forename: Isabel Menezes
authors.initials: IM
authors.lastname: de Bulhões Gomes
authors.forename: Alexandre Nunes
authors.initials: AN
authors.lastname: Ponezi
authors.forename: Edilberto Princi
authors.initials: EP
authors.lastname: Portugal
authors.forename: João Roberto
authors.initials: JR
authors.lastname: Vicente
authors.forename: Ednilson
authors.initials: E
authors.lastname: Davanzo
mesh_terms: D018554:Avena; D001407:Bacillus / Q000201:enzymology*; D005052:Eucalyptus; D006026:Glycoside Hydrolases / Q000032:analysis / Q000302:isolation & purification / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007221:Industry; D013696:Temperature; D014934:Wood; D043325:Xylan Endo-1,3-beta-Xylosidase; D014995:Xylosidases / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology*
chemical_list: D006026:Glycoside Hydrolases; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase