title: Production of xylanolytic enzymes by Aspergillus terricola in stirred tank and airlift tower loop bioreactors.
abstract: Fungi producing high xylanase levels have attracted considerable attention because of their potential industrial applications. Batch cultivations of Aspergillus terricola fungus were evaluated in stirred tank and airlift bioreactors, by using wheat bran particles suspended in the cultivation medium as substrate for xylanase and β-xylosidase production. In the stirred tank bioreactor, in physical conditions of 30°C, 300 rpm, and aeration of 1 vvm (1 l min⁻¹), with direct inoculation of fungal spores, 7,475 U l⁻¹ xylanase was obtained after 36 h of operation, remaining constant after 24 h. In the absence of air injection in the stirred tank reactor, limited xylanase production was observed (final concentration 740 U l⁻¹). When the fermentation process was realized in the airlift bioreactor, xylanase production was higher than that observed in the stirred tank bioreactor, being 9,265 U l⁻¹ at 0.07 vvm (0.4 l min⁻¹) and 12,845 U l⁻¹ at 0.17 vvm (1 l min⁻¹) aeration rate.
authors.affiliation: IBB Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal.
authors.forename: Michele
authors.initials: M
authors.lastname: Michelin
authors.forename: Maria de Lourdes Teixeira de Moraes
authors.initials: Mde L
authors.lastname: Polizeli
authors.forename: Daniel Pereira da
authors.initials: DP
authors.lastname: Silva
authors.forename: Denise Santos
authors.initials: DS
authors.lastname: Ruzene
authors.forename: António Augusto
authors.initials: AA
authors.lastname: Vicente
authors.forename: João Atílio
authors.initials: JA
authors.lastname: Jorge
authors.forename: Héctor Francisco
authors.initials: HF
authors.lastname: Terenzi
authors.forename: José António
authors.initials: JA
authors.lastname: Teixeira
mesh_terms: D001230:Aspergillus / Q000201:enzymology* / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology*; D004043:Dietary Fiber; D005285:Fermentation; D014995:Xylosidases / Q000378:metabolism*
chemical_list: D004043:Dietary Fiber; D014995:Xylosidases; C026579:exo-1,4-beta-D-xylosidase