246 Chapter 8 of the gammaproteobacterial Pseudomonadales IMCC2047 (also known as the MBAE14 family) and the betaproteobacterial Rugosibacter, both carrying divergent CuMMOs. Our data suggested that these microorganisms might be heterotrophs utilizing unknown substrates for both their Cu-MMO and PQQ-dependent alcohol dehydrogenases (PQQ-ADH). Pseudomonadales IMCC2047 also harbors a hydroxylamine oxidoreductase (haoA) along with a cytochrome c-554 (cycB), raising the possibility that they may function as nitrifiers (Mori et al., 2019) - a hypothesis that requires further experimental testing. We propose that these microorganisms could alternatively be using short alkanes or alcohols as substrates. To investigate this, future work should focus on isolating these microorganisms and incubating them under varying conditions with different substrates (ammonium or shortchain alkanes) to better understand their metabolic capabilities. BIOTECHNOLOGICAL OPPORTUNITIES OF N-DAMO (CHAPTER 4 AND 5) In this section, we explore the biotechnological potential for nitrate/nitritedependent anaerobic methane oxidation (N-DAMO), particularly in WWTPs, coupling findings from Chapters 4 and 5. In Chapter 4, we described a stable anoxic and brackish co-culture involving sulfide-oxidizing denitrifiers, anammox bacteria, and N-DAMO organisms under sulfide, ammonium, methane, and nitrate-dependent conditions. Chapter 5 employed a stable anoxic N-DAMO culture enriched with anammox (“Ca. Brocadia spp.”) under methane-rich, nitrate-dependent conditions and exposed to sulfide toxicity. The potential biotechnological applications of such co-cultures lie in their ability to reduce greenhouse gas emissions in WWTPs by utilizing methane and removing nitrogen compounds simultaneously. WWTPs are engineered ecosystems that contribute substantially to greenhouse gas emissions, particularly methane, via sewer systems, their anaerobic treatment and sludge digestion processes (Saunois et al., 2024; Tian et al., 2022). These systems also present an important target for mitigation strategies due to their controlled environment (Guerrero Cruz et al., 2018). Several studies have proposed and successfully enriched in bioreactors microbial populations for simultaneous
RkJQdWJsaXNoZXIy MTk4NDMw