Synthesis of nitrogenase by Paenibacillus sabinae T27 in presence of high levels of ammonia during anaerobic fermentation

Biological nitrogen fixation is usually inhibited by fixed nitrogen. Paenibacillus sabinae T27, a Gram-positive, spore-forming diazotroph, possesses high nitrogenase activity and has 3 copies of nifH (nifH, nifH2, nifH3), copy nifDK, multiple nifHDK-like genes. In this study, we found that P. T27 showed activities not only in low (0–3 mM) concentrations NH4+ but also (30–300 NH4+, no matter whether bacterium was grown flask or fermenter on scale cultivation. qRT-PCR western blotting analyses supported Fe protein MoFe were synthesized under both NH4+. Liquid chromatography-mass spectrometry (LC-MS) analysis revealed encoded nifDK nifH2. The cross-reaction suggested the purified components from nitrogen-limited nitrogen-excess conditions active. This first time to report diazotrophs show presence Our study will provide clue for studying mechanisms concentration • can synthesize active levels ammonia. •Fe proteins absence ammonia are same as those nifDK.