Characterization of a novel Pseudomonas mosselii 9-1 capable of nitrate reduction to ammonium, ammonium assimilation, and denitrification in aerobic conditions

Pseudomonas mosselii 9-1 was isolated from Litopenaeus vannamei aquaculture wastewater and effectively removed ammonium and nitrate, with 98 % of ammonium and 45 % of nitrate removed within 24 h. Moreover, P. mosselii 9-1 tolerated as high as 2500 mg/L of ammonium along with the elimination of approximately 588 mg/L of it within 24 h. KEGG analysis revealed that rather than nitrification, P. mosselii 9-1 removes ammonium via heterotrophic ammonium assimilation, the presence of nirBD and nirK genes implicated reduction to ammonium and aerobic denitrification reduction to gaseous nitrogen, as the pathways involved in NO2- removal. Additionally, P. mosselii 9-1 can transform organic nitrogen to NH3 through ammonification. Single-factor an-alyses revealed a C/N ratio of 18, a temperature of >20 degrees C, pH 6-9, and sodium succinate as a source of carbon, favored the removal of ammonium and nitrate. P. mosselii 9-1 may be a promising biotreatment agent for wastewater containing high ammonium levels.

Automated summary

Pseudomonas mosselii 9-1 isolated from aquaculture wastewater effectively removed 98% of ammonium and 45% of nitrate within 24 hours. It could tolerate up to 2500 mg/L of ammonium and eliminated approximately 588 mg/L within 24 hours. The bacterium utilized heterotrophic ammonium assimilation and aerobic denitrification to remove ammonium through the presence of specific genes, and could also convert organic nitrogen to NH3 through ammonification. The removal of ammonium and nitrate was favored by a C/N ratio of 18, temperature above 20 degrees C, pH 6-9, and sodium succinate as a carbon source. Pseudomonas mosselii 9-1 shows promise as a biotreatment agent for high ammonium wastewater.