Ammonium Production During the Nitrogen-Fixing Process by Wild Paenibacillus Strains and Cell-Free Extract Adsorbed on Nano TiO2 Particles

作者：Shokri Dariush; Emtiazi Giti^*

来源：Journal of Microbiology and Biotechnology, 2010, 20(8): 1251-1258.

DOI：10.4014/jmb.1003.03002

• Ammonium
• Paenibacillus
• nano TiO2 particles
• nitrogenase
• nitrogen-fixing process

During the nitrogen-fixing process, ammonia (NH3) is incorporated into glutamate to yield glutamine and is generally not secreted. However, in this study, NH3-excreting strains of nitrogen-fixing Paenibacillus were isolated from soil. The ammonium production by the Paenibacillus strains was assayed in different experiments (dry biomass, wet biomass, cell-free extract, and cell-free extract adsorbed on nano TiO2, particles) inside an innovative bioreactor containing capsules of N, and H,. In addition, the effects of different N-2 and H-2 treatments on the formation of NH3 were assayed. The results showed that the dry biomass of the strains produced the most NH3. The dry biomass of the Paenibacillus strain E produced the most NH3 at 1.50, 0.34, and 0.27 mu M NH3/mg biomass/h in the presence of N-2 + H-2, N-2, and H-2, respectively, indicating that a combined effluent of N-2 and H-2 was vital for NH3 production. Notwithstanding, a cell-free extract (CFE) adsorbed on nano TiO, particles produced the most NH3 and preserved the enzyme activities for a longer period of time, where the NH3 production was 2.45 ttIVI/mg CFE/h over 17 h. Therefore, the present study provides a new, simple, and inexpensive method of NH3 production.

• 出版日期2010-8