ena-STUDY-Universiteit Gent-12-04-2017-13:36:37:548-605
Isotope fractionation in the biogas allows direct microbial community stability monitoring in anaerobic digestion.
Process monitoring of anaerobic digestion is based on operational parameters, such as pH and volatile fatty acid concentration, that are limping behind on actual microbial community performance. In this study, stable isotope fractionation in the CH4 and CO2 in the biogas was used as an early-warning method to monitor process stability in anaerobic digestion in response to salt stress. A gradual and pulsed increase in the salt concentration resulted in a decrease in methane production. No clear shift in the d13CH4 content could be observed in response to the gradual increase in the salt concentration, and the d13CO2 content of the biogas showed only a clear shift after process failure. In contrast, both the d13CH4 and d13CO2 content in the biogas changed in response to the pulsed increase in the salt concentration. This change preceded the decrease in methane production. A significantly different bacterial and archaeal community profile was observed between the DNA and RNA level, which was also reflected in a different response in the d13CH4 and d13CO2 content. This emphasizes that isotope fractionation in the biogas can be used to predict process stability in anaerobic digestion, as it directly reflects shifts in the total and active microbial community.
Process monitoring of anaerobic digestion is based on operational parameters, such as pH and volatile fatty acid concentration, that are limping behind on actual microbial community performance. In this study, stable isotope fractionation in the CH4 and CO2 in the biogas was used as an early-warning method to monitor process stability in anaerobic digestion in response to salt stress. A gradual and pulsed increase in the salt concentration resulted in a decrease in methane production. No clear shift in the d13CH4 content could be observed in response to the gradual increase in the salt concentration, and the d13CO2 content of the biogas showed only a clear shift after process failure. In contrast, both the d13CH4 and d13CO2 content in the biogas changed in response to the pulsed increase in the salt concentration. This change preceded the decrease in methane production. A significantly different bacterial and archaeal community profile was observed between the DNA and RNA level, which was also reflected in a different response in the d13CH4 and d13CO2 content. This emphasizes that isotope fractionation in the biogas can be used to predict process stability in anaerobic digestion, as it directly reflects shifts in the total and active microbial community.