Separating and Characterizing Functional Nitrogen Degraders via Magnetic Nanoparticle-Mediated Isolation

Magnetic nanoparticle-mediated isolation (MMI) is a new method for isolating active functional microbes from complex microorganisms without substrate labeling. In this study, the composition and properties of magnetic nanoparticles (MNPs) were characterized by a number of techniques, indicating that MNPs have characteristics such as microinterfaces and can be efficiently fixed on the surface of microbial cells. It also introduced the MMI technology in activated sludge after stable long-term treatment. With further addition of promotor carbon sources, the enrichment of the functional nitrogen degraders in MMI was significantly higher than in samples without MNPs, showing the advantages of MMI in identifying the active degraders. Redundancy analysis (RDA) also showed that the functional nitrogen degraders such as Comamonadaceae_unclassified and Thiobacillus absolutely dominated in situ ammonia degradation, and the change in dominant genera had the same trend as the degradation rate of ammonia nitrogen. In the magnetically functionalized system, the separated functional nitrogen degraders significantly improved ammonia nitrogen degradation efficiency, making it basically stable at more than 80%, up to 91.6%. These results prove that the complex flora created after the addition of MNPs is more adaptable to newly introduced pollutants, and MMI is a powerful tool for studying pollutant-degrading microorganisms under in situ conditions.

Metabolic encephalopathy caused by nitrous oxide (‘laughing gas’) induced hyperammonaemia

A 26-year-old man presented at the emergency department with confusion and decreased consciousness after several days of vomiting. In the preceding 6 months, he had used a 2-litre tank of nitrous oxide (N2O) weekly. His metabolic encephalopathy was caused by hyperammonaemia which probably resulted from interference of N2O-induced vitamin B12 deficiency with ammonia degradation. A catabolic state might have contributed to the hyperammonaemia in this case. After treatment with vitamin B12 and lactulose, both his consciousness and hyperammonaemia improved. He reported no residual complaints after 3 months of follow-up. Since N2O is increasingly used as a recreational drug, we recommend considering hyperammonaemia as a cause of metabolic encephalopathy in cases of N2O use and altered mental status.

PENENTUAN TINGKAT KANDUNGAN AMONIAK, NITRIT, DAN NITRAT PADA REMBESAN SAMPAH LOKASI PEMBUANGAN AKHIR (LPA) AIR DINGIN KOTA PADANG

Determination of amoniac, nitrite, and nitrate content in seepage waste water in landfill area in cold water, Padang have been done using spectrophotometric method. Sample took from sequencing ofseepage waste water treatment process. The results showed that the ammonia, nitrite, and nitrate content in seepage waste water were 137.612 to 400.298 mg/ L, 0.34 to 0.756 mg/ L, and 0.682 to5.842 mg/ L, respectively. The differences of ammonia, nitrite, and nitrate content in seepage waste water and ammonia and nitrite contents tend to decrease while the nitrate content tends to increase. The rate of ammonia degradation in water seepage was different for each sampling place where the rate of degradation was greatest in seepage water waste treatment II. This degradation is expected to reduce the level of pollution on the environment.