The nitrogen removal characterization of a cold-adapted bacterium: Bacillus simplex H-b

Area of Science:

• Environmental Microbiology
• Wastewater Treatment Technologies
• Bioremediation

Background:

• Biological nitrogen removal processes are often hindered by low temperatures.
• Developing microbial solutions for effective nitrogen removal in cold environments is crucial for wastewater treatment.

Purpose of the Study:

• To isolate and identify a psychrotrophic bacterium capable of heterotrophic nitrification and aerobic denitrification.
• To evaluate the nitrogen removal efficiency of the isolated strain at low temperatures.
• To investigate the low-temperature resistance mechanisms of the identified bacterium.

Main Methods:

• Isolation and identification of a psychrotrophic bacterium from environmental samples.
• Assessing the removal efficiencies of nitrate-N, nitrite-N, and ammonium-N at various temperatures (5-37 °C).
• Measuring adenosine triphosphate (ATP) levels and extracellular polymeric substances (EPS) formation under different temperature conditions.

Main Results:

• Bacillus simplex H-b was identified as a psychrotrophic bacterium with heterotrophic nitrification and aerobic denitrification capabilities.
• At 10 °C, removal efficiencies for nitrate-N, nitrite-N, and ammonium-N were 67.29%, 78.69%, and 82.16%, respectively.
• Increased ATP accumulation and EPS formation at lower temperatures suggest a robust cold-stress resistance mechanism in strain H-b.

Conclusions:

• Bacillus simplex H-b demonstrates significant nitrogen removal efficacy across a wide temperature range, including low temperatures.
• The strain's ability to withstand cold conditions makes it a promising candidate for nitrogen-contaminated wastewater treatment, particularly in colder climates.
• The study highlights the potential of microbial solutions for overcoming temperature-related limitations in biological wastewater treatment.