Enhancing biological conversion of NO to N 2 O by utilizing thermophiles instead of mesophiles

• Published in: Chemosphere (Oxford) 2023-12, Vol.350, p.141037
• Main Authors: Li, Dan, Sun, Zhuqiu, Luo, Ga, Lu, Lichao, Zhang, Shaobo, Xi, Jinying
• Format: Article
• Language: English
• ISSN: 1879-1298
• DOI: 10.1016/j.chemosphere.2023.141037

The production of nitrous oxide (N O) through the biological denitrification of nitric oxide (NO) from flue gases has recently been achieved. Although the temperature of flue gas after desulphurization is usually 45-70 °C, all previous studies conducted microbial denitrification of NO under mesophilic conditions (22-35 °C). This study investigated the biological conversion of NO to N O in both mesophilic (35-45 °C) and thermophilic conditions (45-50 °C). The results showed that temperature has a great impact on N O production, with a maximum conversion efficiency (from NO to N O) of 82% achieved at 45 °C, which is obviously higher than the reported conversion efficiencies (24-71%) under mesophilic conditions. Additionally, high-throughput sequencing result showed that the genera Enterococcus, Clostridium, Romboutsia, and Streptococcus were closely related to NO denitrification and N O production. Microbial communities at 40 and 45 °C had greater metabolizing capacities for polymeric carbon sources. This study suggests that thermophilic condition (45 °C) is more suitable for biological production of N O from NO.