title: Mixed culture fermentation and media optimization by response surface model: Streptomyces and Brachybacterium species in bioflocculant production.
abstract: 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 (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 µm.
authors: Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa. UNwodo@ufh.ac.za.
authors: Uchechukwu U
authors: UU
authors: Nwodo
authors: Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa. AOkoh@ufh.ac.za.
authors: Anthony I
authors: AI
authors: Okoh
mesh_terms: D000192:Actinomycetales / Q000254:growth & development / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D003470:Culture Media / Q000737:chemistry; D004734:Energy Metabolism; D005285:Fermentation; D013302:Streptomyces / Q000254:growth & development / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media