Xylanases from Aspergillus niger, Aspergillus niveus and Aspergillus ochraceus produced under solid-state fermentation and their application in cellulose pulp bleaching
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This study describes the production of xylanases from Aspergillus niveus, A. niger, and A. ochraceus under solid-state fermentation using agro-industrial residues as substrates. Enzyme production was improved using a mixture of wheat bran and yeast extract or peptone. When a mixture of corncob and wheat bran was used, xylanase production from A. niger and A. ochraceus increased by 18%. All cultures were incubated at 30 °C at 70–80% relative humidity for 96 h. For biobleaching assays, 10 or 35 U of xylanase/g dry cellulose pulp were incubated at pH 5.5 for 1 or 2 h, at 55 °C. The delignification efficiency was 20%, the brightness (percentage of ISO) increased two to three points and the viscosity was maintained confirming the absence of cellulolytic activity. These results indicated that the use of xylanases could help to reduce the amount of chlorine compounds used in cellulose pulp treatment.
KeywordsAspergillus Cellulase-free xylanases Biobleaching Kappa number Cellulose pulp
This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). J.A.J., H·F.T. and M.L.T.M.P. are Research Fellows of CNPq. This work was part of Master Dissertation of J.H.A.B. submitted to the Departamento de Biologia—FFCLRP/USP. The authors thank Ricardo F. Alarcon and Maurício de Oliveira for technical assistance.
- 1.Angayarknni J, Palaniswamy M, Pradeep BV, Swaminathan K (2006) Biochemical substitution of fungal xylanases for prebleaching of hardwood kraft pulp. Afr J Biotechnol 5:921–929Google Scholar
- 6.Rizzatti ACS, Jorge JA, Terenzi HF, Rechia CGV, Polizeli MLTM (2001) Purification and properties of a thermostable extracellular β-d-xylosidase produced by a thermotolerant Aspergillus phoenicis. J Ind Microbiol Biotechnol 4:265–275Google Scholar
- 10.Chadha BS, Kanwar SS, Garcha HS (1995) Simultaneous saccharification and fermentation of rice straw into ethanol. Acta Microbiol Immunol Hung 42:71–75Google Scholar
- 11.Emerson R (1941) An experimental study of the life cycles and taxonomy of Allomyces. Lloydia 4:77–144Google Scholar
- 13.McIlvaine TC (1921) A buffer solution for colorimetric comparison. J Biol Chem 49:183–186Google Scholar
- 14.Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the Folin phenol reagent. J Biol Chem 193:267–275Google Scholar
- 15.TAPPI test methods (1996) Technical association of the pulp and paper industry. TAPPI Press, AtlantaGoogle Scholar