Influence of carbon source on nitrate removal by nitrate-tolerant Klebsiella oxytoca CECT 4460 in batch and chemostat cultures
- Consejo Superior de Investigaciones Cientificas, Granada (Spain)
- Swiss Federal Inst. for Environmental Science and Technology, Duebendorf (Switzerland). Dept. of Microbiology
The nitrate-tolerant organism Klebsiella oxytoca CECT-4460 tolerates nitrate at concentrations up to 1 M and is used to treat wastewater with high nitrate loads in industrial wastewater treatment plants. The authors studied the influence of the C source (glycerol or sucrose or both) on the growth rate and the efficiency of nitrate removal under laboratory conditions. With sucrose as the sole C source the maximum specific growth rate was 0.3 h{sup {minus}1}, whereas with glycerol it was 0.45 h{sup {minus}1}. In batch cultures K. oxytoca cells grown on sucrose or glycerol were able to immediately use sucrose as a sole C source, suggesting that sucrose uptake and metabolism were constitutive. In contrast, glycerol uptake occurred preferentially in glycerol-grown cells. Independent of the preculture conditions, when sucrose and glycerol were added simultaneously to batch cultures, the sucrose was used first, and once the supply of sucrose was exhausted, the glycerol was consumed. Utilization of nitrate as an N source occurred without nitrite of ammonium accumulation when glycerol was used, but nitrite accumulated when sucrose was used. In chemostat cultures K. oxytoca CECT 4460 efficiently removed nitrate without accumulation of nitrite or ammonium when sucrose, glycerol, or mixtures of these two C sources were used. The growth yields and the efficiencies of C and N utilization were determined at different growth rates in chemostat cultures. Regardless of the C source, yield carbon (Y{sub C}) ranged between 1.3 and 1.0 g (dry weight) per g of sucrose C or glycerol C consumed. Regardless of the specific growth rate and the C source, yield nitrogen (Y{sub N}) ranged from 17.2 to 12.5 g (dry weight) per g of nitrate N consumed.
- OSTI ID:
- 642344
- Journal Information:
- Applied and Environmental Microbiology, Vol. 64, Issue 8; Other Information: PBD: Aug 1998
- Country of Publication:
- United States
- Language:
- English
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