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Production of xylanolytic enzymes by Aspergillus terricola in stirred tank and airlift tower loop bioreactors.

Research paper by Michele M Michelin, Maria de Lourdes Teixeira de Moraes Mde L Polizeli, Daniel Pereira da DP Silva, Denise Santos DS Ruzene, António Augusto AA Vicente, João Atílio JA Jorge, Héctor Francisco HF Terenzi, José António JA Teixeira

Indexed on: 01 Jun '11Published on: 01 Jun '11Published in: Journal of Industrial Microbiology & Biotechnology



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.