Author/Authors :
aouati, m. k. university of constantine1 - faculty of exact sciences - water treatment and pollution laboratory, (wtpl), department of chemistry, algeria , bougherara, h. university of constantine1 - faculty of exact sciences - water treatment and pollution laboratory, (wtpl), department of chemistry, Algeria , ouled-haddar, h. university of mohamed seddik benyahia - faculty of nature and life science - laboratory of molecular toxicology, Jijel, Algeria , sifour, m. university of mohamed seddik benyahia - faculty of nature and life science - laboratory of molecular toxicology, Jijel, Algeria , aissaoui, s. university of mohamed seddik benyahia - faculty of nature and life science - laboratory of molecular toxicology, Jijel, Algeria , kebabi, b. university of constantine1 - faculty of exact sciences - water treatment and pollution laboratory, (wtpl), department of chemistry, Algeria
Abstract :
Heterotrophic denitrification is one of the most selective and advanced method for nitrate removal, it is usually inhibited by insufficient carbon sources. From the wastewater treatment plant (WWTP) of El Menia (Constantine), Algeria, five bacterial strains were isolated but only the strains N5 and N6 were identified. The strains were preliminarily identified using biochemical tests and then a method based on the similarity of the PCR- 16S rRNA. 16S rRNA gene sequence analysis indicated that both strains were most closely related to Enterobacter hormaechei with sequence similarities of 99%. Both strains showed an excellent capability to remove nitrate and to transform carbon substances namely methanol and sodium-succinate to carbon dioxide. This process was accompanied by a slight rise in pH with a simultaneous production of nitrogen gas as the end product at 35°C. Nitrate was removed after 48 h of incubation. Thus, the anaerobic denitrification ability of strains N5 and N6 has been proved. Sodium-succcinate is the most favorable carbon source for denitrification by both strains (N5 and N6). Furthermore, strains N5 and N6 could effectively remove nitrate at low C/N ratios and under conditions where the temperature is elevated, which would benefit nitrate removal from the wastewater.
Keywords :
Enterobacter hormaechei , Heterotrophic denitrificationl , Nitrate , C , N ratio
