The Effects of Different Carbon Sources and C/N Ratio on Microbial Denitrification

Authors: GÜLTEN ÖKMEN KURUCUOĞLU, ÖMER FARUK ALGUR

Abstract: The effects of different carbon sources (ethanol, methanol and acetic acid) and C/N ratios (0,5; 1; 1,5; 2; 2,5) on the microbial denitrification in batch culture were investigated. For this purpose Paracoccus denitrificans and Pseudomonas stutzeri were used as denitrifiers. For all experiments, the initial NO 3 concentrations were constant at 100 mg/l. During the incubation period of 66 hours, nitrate, nitrite and microorganism concentrations were determined spectrophotometrically at certain intervals. When ethanol was used as a carbon source, the highest NO 3 reductions for P. denitrificans and P. stutzeriwere found to be 40% (C/N = 1) and 32% (C/N = 2,5), respectively. When methanol was used as a carbon source, the highest NO 3 reductions for these two species were 35% (C/N = 0,5) and 20% (C/N = 1), respectively. On the other hand, 29% NO 3 reduction (C/N = 0,5) for P. denitrificans and 59% NO 3 reduction (C/N = 1) for P. stutzeri were obtained when acetic acid was used as a carbon source.

Keywords: Batch culture, denitrification, Pseudomonas stutzeri, Paracoccus denitrificans.

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