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International Journal of Chemical Engineering
Volume 2012, Article ID 303874, 9 pages
http://dx.doi.org/10.1155/2012/303874
Research Article

Canonical Analysis Technique as an Approach to Determine Optimal Conditions for Lactic Acid Production by Lactobacillus helveticus ATCC 15009

1Center of Technology and Regional Development, Federal University of Paraíba, 58051-900 João Pessoa, PB, Brazil
2Chemical Engineering College, Federal University of Uberlândia, 38408-100 Uberlândia, Brazil

Received 26 June 2011; Revised 8 October 2011; Accepted 25 October 2011

Academic Editor: Iftekhar A. Karimi

Copyright © 2012 Marcelo Teixeira Leite 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

The response surface methodology and canonical analysis were employed to find the most suitable conditions for Lactobacillus helveticus to produce lactic acid from cheese whey in batch fermentation. The analyzed variables were temperature, pH, and the concentrations of lactose and yeast extract. The experiments were carried out according to a central composite design with three center points. An empiric equation that correlated the concentration of lactic acid with the independent variables was proposed. The optimal conditions determined by the canonical analysis of the fitted model were 40°C, pH 6.8, 82 g/L of lactose, and 23.36 g/L of yeast extract. At this point, the lactic acid concentration reached 59.38 g/L. A subsequent fermentation, carried out under optimal conditions, confirmed the product concentration predicted by the adjusted model. This concentration of lactic acid is the highest ever reported for Lactobacillus helveticus ATCC 15009 in batch process using cheese whey as substrate.