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Enzyme Research
Volume 2014, Article ID 703291, 8 pages
http://dx.doi.org/10.1155/2014/703291
Research Article

Optimisation of Cellulase Production by Penicillium funiculosum in a Stirred Tank Bioreactor Using Multivariate Response Surface Analysis

1Bioprocess Development Laboratory, Biochemical Engineering Department, School of Chemistry, Federal University of Rio de Janeiro, P.O. Box 68542, 21945-970 Rio de Janeiro, RJ, Brazil
2Biotechnology Division, Research and Development Center, PETROBRAS, Avenida Horácio Macedo, 950 Ilha do Fundão, 21941-915 Rio de Janeiro, RJ, Brazil

Received 2 February 2014; Revised 10 June 2014; Accepted 11 June 2014; Published 25 June 2014

Academic Editor: Raffaele Porta

Copyright © 2014 Marcelle Lins de Albuquerque de Carvalho et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Increasing interest in the production of second-generation ethanol necessitates the low-cost production of enzymes from the cellulolytic complex (endoglucanases, exoglucanases, and β-glucosidases), which act synergistically in cellulose breakdown. The present work aimed to optimise a bioprocess to produce these biocatalysts from the fungus Penicillium funiculosum ATCC11797. A statistical full factorial design (FFD) was employed to determine the optimal conditions for cellulase production. The optimal composition of culture media using Avicel (10 g·L−1) as carbon source was determined to include urea (1.2 g·L−1), yeast extract (1.0 g·L−1), KH2PO4 (6.0 g·L−1), and MgSO4·7H2O (1.2 g·L−1). The growth process was performed in batches in a bioreactor. Using a different FFD strategy, the optimised bioreactor operational conditions of an agitation speed of 220 rpm and aeration rate of 0.6 vvm allowed the obtainment of an enzyme pool with activities of 508 U·L−1 for FPase, 9,204 U·L−1 for endoglucanase, and 2,395 U·L−1 for β-glucosidase. The sequential optimisation strategy was effective and afforded increased cellulase production in the order from 3.6 to 9.5 times higher than production using nonoptimised conditions.