Comparative effects of inorganic and organic nitrogen on the growth and microcystin production of Microcystis aeruginosa

• Published in: World journal of microbiology & biotechnology 2015-05, Vol.31 (5), p.763-772
• Main Authors: Yan, YangWei, Dai, RuiHua, Liu, Yan, Gao, JiaYi, Wu, XuanHao
• Format: Article
• Language: English
• Subjects: Alanine; Alanine - metabolism; Algae; Algal blooms; Amino acids; Ammonia; Ammonia - metabolism; Analysis; Applied Microbiology; arginine; Biochemistry; Biomass; Biomedical and Life Sciences; Biosynthesis; Biotechnology; Blooms; Chromatography; Cyanobacteria; Environmental Engineering/Biotechnology; Eutrophication; Isotope Labeling; isotopes; Leucine; Life Sciences; Mass spectrometry; Microbiology; microcystin-LR; Microcystins; Microcystins - metabolism; Microcystis; Microcystis - growth & development; Microcystis - metabolism; Microcystis aeruginosa; Nitrogen; Nitrogen Isotopes - metabolism; Organic nitrogen; Original Paper; Residues; Scientific imaging; Solvents; Studies; tandem mass spectrometry; Toxins; Water pollution; Water quality
• ISSN: 0959-3993; 1573-0972
• DOI: 10.1007/s11274-015-1829-y

Nitrogen causes the frequent occurrence of harmful algal blooms and possible microcystin production. The effects of ammonia and alanine (Ala) on the growth and microcystin production of Microcystis aeruginosa were investigated using an isotope tracer (¹⁵N). The results indicated that Ala was directly used by M. aeruginosa and contributed to biomass formation amounting to 2.1 × 10⁷ cells mL⁻¹on day 48, compared with only 6.2 × 10⁶cells mL⁻¹from ammonia alone. Microcystin-LR production with Ala was less than that of ammonia, which peaked at 50.2 fg cell⁻¹on day 6. Liquid chromatographic analysis with tandem mass spectrometry of¹⁵N–microcystin-LR suggested that¹⁵N from ammonia was probably synthesized into the arginine residue. By contrast,¹⁵N from Ala was assimilated into the Ala, leucine, the iso-linked (2R,3S)-3-methylaspartic acid, arginine, and certain unusual C₂₀amino acid residues. The results represent the forward steps in the determination of the nitrogen forms that fuel toxin production and blooms.