Mixed Culture Fermentation and Media Optimization by Response Surface Model: Streptomyces and Brachybacterium Species in Bioflocculant Production

Molecules

Uchechukwu U. Nwodo¹ 

关键词: bioflocculant;    Brachybacterium;    mixed culture;    optimization;    Streptomyces;   

DOI  :  10.3390/molecules190811131

来源: mdpi

【 摘 要 】

The biofloculant production potential of a consortium of Streptomyces and Brachybacterium species were evaluated. Optimum bioflocculant yields (g/L) and flocculation activities (%) were observed for the following preferred nutritional sources: glucose (56%; 2.78 ± 0.15 g/L), (NH₄)₂NO₃ (53%; 2.81 ± 0.37 g/L) and CaSO₄·H₂O (47%; 2.19 ± 0.13 g/L). A Plackett-Burman design revealed the critical fermentation media components. The concentrations of these components were optimized [glucose; 16.0, (NH₄)₂NO₃; 0.5 and CaSO₄·H₂O; 1.2 (g/L)] through a central composite design with optimum bioflocculant yield of 3.02 g/L and flocculation activity of 63.7%. The regression coefficient (R² = 0.6569) indicates a weak estimation of the model’s adequacy and a high lack-of-fit value (34.1%). Lack of synergy in the consortium may have been responsible for the model inadequacy observed. FTIR spectrometry showed the bioflocculant to be a heteropolysaccharide, while SEM imaging revealed an amorphous loosely arranged fluffy structure with interstial spacing of less than 1 µm.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.