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Electronic Journal of Biotechnology
Universidad Católica de Valparaíso
ISSN: 0717-3458
Vol. 10, No. 1, 2007, pp. 1-8
Bioline Code: ej07012
Full paper language: English
Document type: Research Article
Document available free of charge

Electronic Journal of Biotechnology, Vol. 10, No. 1, 2007, pp. 1-8

 en Production of lignocellulolytic enzymes by Aspergillus niger check for this species in other resources biofilms at variable water activities
Villena, Gretty K. & Gutiérrez-Correa, Marcel

Abstract

Lignocellulolytic enzyme production by Aspergillus niger check for this species in other resources was compared both in submerged fermentation (SF) and biofilm fermentation (BF) at varying water activities. Maximal filter paper activity, endoglucanase and xylanase activities were much higher in BF (2.96, 4.7 and 4.61 IU ml-1, respectively) than in SF cultures (1.71, 1.31 and 2.3 IU ml-1, respectively) but biomass yields were lower in BF than in SF ( 0.338 g g-1 and 0.431 g g-1, respectively). In the presence of 20% ethylene glycol (aw = 0.942) the enzyme activities decreased in both systems but BF still had higher levels (1.0, 1.0 and 2.6 IU ml-1, respectively) than SF cultures (0.6, 0.7 and 1.5 IU ml-1, respectively). An increase in xylanase specific activity of more than 2 fold (from 4.2 to 10.2 IU mg-1 biomass) was observed in the presence of 20% ethylene glycol, suggesting differential regulatory mechanisms in biofilm fermentation related to cell adhesion.

Keywords
biofilm, cellulase, ethylene glycol, water activity, xylanase

 
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