Saedi Atefeh, Naghavi Nafiseh Sadat, Farazmand Abbas, Zare Davood, Mohammadi-Sichani Maryam
Department of Microbiology, Falavarjan Branch, Islamic Azad University, Isfahan, Iran.
Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran.
Environ Technol. 2025 Aug;46(19):3739-3749. doi: 10.1080/09593330.2023.2283781. Epub 2023 Dec 7.
The objective of this study was to isolate specific heterotrophic aerobic denitrifying bacteria from a wastewater treatment plant and employ them in an attached growth system for wastewater denitrification.
To isolate and screen aerobic denitrifiers, Denitrifying Medium (DM) and Screen Medium (GN) were utilized. The Polymerase Chain Reaction (PCR) technique and 16S rDNA sequencing were used to identify the isolates. The formation of biofilms by selected isolates on ceramic media was examined using a Scanning Electron Microscope (SEM). This study also investigated various variables for nitrate removal, including temperature, Carbon/Nitrogen ratio (C/N), and the carbon source. A series of experiments were conducted to gauge nitrate removal under optimal variable values.
Six purified strains exhibited the highest denitrification efficiency in less than 30 h. species were chosen for additional experiments. Denitrification efficiencies ranged from a low of 71.4% (at a temperature of 30 °C, C/N ratio of 17, and citrate as the carbon source) to a high of 98.9% (at a temperature of 33 °C, C/N ratio of 8, and citrate as the carbon source). The average denitrification efficiency was 84.02%. Optimal nitrate removal occurred at temperatures around 30-31 °C and C/N ratios of approximately 5.8-6.5.
This study demonstrates that aerobic denitrifying bacteria can effectively remove nitrate from aqueous solutions.
本研究的目的是从一家污水处理厂分离出特定的异养需氧反硝化细菌，并将其应用于附着生长系统中进行废水反硝化。
为了分离和筛选需氧反硝化菌，使用了反硝化培养基（DM）和筛选培养基（GN）。采用聚合酶链反应（PCR）技术和16S rDNA测序对分离菌株进行鉴定。使用扫描电子显微镜（SEM）检查所选菌株在陶瓷介质上生物膜的形成情况。本研究还调查了硝酸盐去除的各种变量，包括温度、碳氮比（C/N）和碳源。进行了一系列实验以测定最佳变量值下的硝酸盐去除情况。
六种纯化菌株在不到30小时内表现出最高的反硝化效率。选择菌株进行进一步实验。反硝化效率范围从低至71.4%（温度为30°C、C/N比为17且以柠檬酸盐作为碳源时）到高至98.9%（温度为33°C、C/N比为8且以柠檬酸盐作为碳源时）。平均反硝化效率为84.02%。在温度约为30 - 31°C和C/N比约为5.8 - 6.5时硝酸盐去除效果最佳。
本研究表明需氧反硝化细菌可有效去除水溶液中的硝酸盐。
