Effects of four physical and chemical factors on the nitrification activity of strain XH1

Abstract:

[Background] The enrichment and culture technology based on the nitrifying bacterial community show the efficiency and stability in removing ammonia nitrogen, nitrite nitrogen and other harmful nitrogen from the aquaculture water. However, only a few studies are available on nitrifying functional strains for the targeted cultivation of nitrifying bacterial community in aquaculture. [Objective] To study the effects of salinity, pH, temperature and ventilation on the growth and nitrification activity of strain XH1 isolated from nitrifying bacterial community. [Methods] Different gradients of salinity, pH, temperature and ventilation were assayed. The growth of strain XH1 and the corresponding removal effect on ammonia and nitrite nitrogen were analyzed by counting the number of bacteria and measuring the concentrations of ammonia and nitrite nitrogen, respectively. [Results] Strain XH1 could grow well under the conditions of salinity 5‰?35‰, pH 6.0?9.0, temperature 15?45 °C and ventilation 0.5?1 V/(V·min). The maximum content of bacteria reached the level of 2.34×109 cells/mL. Under the condition of salinity 5‰?35‰, pH 6.0?9.0, temperature 15?30 °C, and ventilation capacity 0.5 V/(V·min), the removal efficiency of ammonia nitrogen was significant (P<0.05). The highest removal rate of ammonia nitrogen in the culture solution could reach 86%?97% on 1?3 d, but then the concentration of ammonia nitrogen increased slightly in the following days. In addition, the highest removal rate of nitrite nitrogen was up to 68%. [Conclusion] The strain XH1 had a good adaptability to major environmental factors such as salinity, pH, and temperature. With the excellent removal ability on ammonia nitrogen, strain XH1 could be used as an alternative strain for the agents’ research on harmful nitrogen prevention and control in medium-low-salinity aquaculture ponds.