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

作者：Nwodo Uchechukwu U^*; Okoh Anthony I

来源：Molecules, 2014, 19(8): 11131-11144.

DOI：10.3390/molecules190811131

• bioflocculant
• Brachybacterium
• mixed culture
• optimization
• Streptomyces

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)(2)NO3 (53%; 2.81 +/- 0.37 g/L) and CaSO4 center dot 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)(2)NO3; 0.5 and CaSO4 center dot 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 (R-2 = 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 mu m.

• 出版日期2014-8