RESUMO
Piggery wastewater was used as a cheap alternative medium for a bioflocculant-producing bacterial flora B-737. Effects of COD concent, addition of ammonium oxalate or phosphate on the cell growth and bioflocculant yield were investigated, and the fermentation kinetics was studied in the optimal culture media. The results showed that the piggery wastewater (COD was about 3000 mg x L(-1), TN was about 170 mg x L(-1)) had a suitable C/N ratio for the growth and fermentation of flora B-737, with addition of only 1.6 g x L(-1) K2HPO4 and 0.8 g x L(-1) KH2PO4, flora B-737 grew well and the bioflocculant yield reached 1.5 g x L(-1), in the meantime, the COD and TN of the wastewater was reduced by 61.9% and 53.6%, respectively. Not only was the medium cost reduced by over 90% , but it was a new way to recycle piggery wastewater. In addition, the dynamic models on cell growth and flocculants formation in the fermentation process of B-737 were established according to the equation of Logistic and Luedeking-Piret, respectively.
