Heterotrophic nitrification–aerobic denitrification by novel isolated bacteria

Abstract

Three novel strains capable of heterotrophic nitrification-aerobic denitrification were isolated from the landfill leachate treatment system. Based on their phenotypic and phylogenetic characteristics, the isolates were identified as Agrobacterium sp. LAD9, Achromobacter sp. GAD3 and Comamonas sp. GAD4, respectively. Batch tests were carried out to evaluate the growth and the ammonia removal patterns. The maximum growth rates as determined from the growth curve were 0.286, 0.228, and 0.433 h(-1) for LAD9, GAD3 and GAD4, respectively. The maximum aerobic nitrification-denitrification rate was achieved by the strain GAD4 of 0.381 mmol/l h, followed by LAD9 of 0.374 mmol/l h and GAD3 of 0.346 mmol/l h. Moreover, hydroxylamine oxidase and periplasmic nitrate reductase were successfully expressed in all the isolates. The relationship between the enzyme activities and the aerobic nitrification-denitrification rates revealed that hydroxylamine oxidation may be the rate-limiting step in the heterotrophic nitrification-aerobic denitrification process. The study results are of great significance to the wastewater treatment systems where simultaneous removal of carbon and nitrogen is desired.

Nitrate Removal from Wastewater through Biological Denitrification with OGA 24 in a Batch Reactor

“…A comparison with the literature confirms that the performance of the Azospira sp. OGA 24 are in line (sometimes better) of the most common bacteria employed in the biological treatment of polluted waters [7,12,23,[27][28][29]. …”

Potential of Rhodobacter capsulatus Grown in Anaerobic-Light or Aerobic-Dark Conditions as Bioremediation Agent for Biological Wastewater Treatments

“…isolated from the soil [42]. Further investigations are necessary to evaluate if heterotrophic nitrification [43] could be one of the well-known metabolisms of R. capsulatus.…”

Mathematical simulating the process of aerobic granular sludge treating high carbon and nitrogen concentration wastewater

“…With the increase of C/N in inflow, the AOB and nitrite oxidizing bacteria (NOB) significantly decrease, while the heterotrophic bacteria gradually increase [20,21]. In recent years, there are many reports about heterotrophic nitrification and aerobic denitrification [22][23][24]. Different from autotrophic nitrifiers, heterotrophicnitrifying bacteria can simultaneously using carbon and nitrogen pollutants.…”

“…On the other hand, in a high carbon and nitrogen wastewater treatment, a strong aeration is generally necessary, which might cause high dissolved oxygen (DO) concentration in the particles. And researches [22,23] showed that denitrification could be carried out in the presence of oxygen.…”