Potato starch wastewater was used for bioflocculant-producing bacteria Rhodococcus erythropolis to produce bioflocculant. Effects of extra phosphate and nitrogen in potato starch wastewater medium on bioflocculant yield and its flocculating activity were discussed. In addition, solution pH values and concentrations of COD, ammonium, and total phosphorus (TP) in the fermentation process were examined, and growth and producing kinetics of the bacteria were described by using Logistic and Luedeking-Piret models. Furthermore, settlement of the potato starch wastewater by this bioflocculant was investigated. The bioflocculant yield and its flocculating activity increased to 0.96g/L and 92.8% when the extra phosphate (K2HPO4: KH2PO4=2:1, w/w) and nitrogen were adjusted to 6g/L and 2g/L, respectively. During the logarithm phase, cell dry weight, cell density OD600, and the number of colonies were increased to 1.58g/L, 0.86 and 5.3×107cfu/mL, respectively. Concentrations of COD, ammonium, and TP of the potato starch medium were consumed rapidly from 7836, 975, and 712mg/L to 1736, 188, and 146mg/L, respectively. After the fermentation, pH value of the potato starch medium was slightly decreased to 6.5. The bioflocculant obtained during the strain's metabolism mainly contained 96.2% of polysaccharide, and there was almost no protein. Cell growth and bioflocculant production could be simulated with both the Logistic and Luedeking-Piret equations pretty well. Furthermore, when the bioflocculant dose was adjusted to 30mg/L, it can remove 48.6% of COD and 71.9% of turbidity from the potato starch wastewater in this study.
郭俊元, 张宇哲, 赵净. 淀粉废水生产微生物絮凝剂及发酵动力学特征[J]. 中国环境科学, 2016, 36(9): 2681-2688.
GUO Jun-yuan, ZHANG Yu-zhe, ZHAO Jing. Production and fermentation kinetics characteristics of a bioflocculant by using potato starch wastewater. CHINA ENVIRONMENTAL SCIENCECE, 2016, 36(9): 2681-2688.
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