Title: Flocculation of a lactic acid fermentation broth by gelatin

Authors: Lijuan Wang; Qunhui Wang; Yan Li; Daqi Cao; Tichang Sun

Addresses: Department of Environmental Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing, 100083, China ' Department of Environmental Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing, 100083, China ' Department of Environmental Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing, 100083, China ' Department of Environmental Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing, 100083, China ' Department of Environmental Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing, 100083, China

Abstract: In the current study, flocculation of a lactic acid (LA) fermentation broth with three kinds of flocculants was performed in order to reduce membrane pollution during its subsequent electrodialysis. Gelatin was selected as the most suitable flocculant in comparison with others in terms of flocculation rate (FR), suspended solid (SS) removal rate, and filtration flux of the supernatant. Optimal flocculation conditions included the addition of 0.3 g/L gelatin, followed by 7 min stirring at 50°C. Under such conditions, the FR, SS removal rate, and filtration flux of the supernatant were 94.21%, 91.44%, and 800 mL/(min • m²), respectively. The average particle diameter of SS after flocculation (Dav) dropped by 66.48%, and the LA loss was 3.63%. The results indicate that gelatin flocculation can be applied to LA fermentation broths. The method proposed here can effectively remove SS and enhance the filtration flux, thereby decreasing membrane pollution and ensuring LA purity.

Keywords: lactic acid; fermentation broths; gelatin flocculation; particle size; HPLC; membrane pollution; electrodialysis; flocculants; flocculation rate; suspended solid removal; filtration flux; laser Doppler electrophoresis; high performance liquid chromatography.

DOI: 10.1504/IJEP.2013.054022

International Journal of Environment and Pollution, 2013 Vol.51 No.3/4, pp.255 - 268

Received: 03 Sep 2011
Accepted: 04 Apr 2012
Published online: 28 Feb 2014 *

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