RT-RiboSyn Used to Investigate the Specific Growth Rate of Methanogenic Populations in Anaerobic Digesters

RT-RiboSyn, a method that has been shown to measure the specific growth rate of pure cultures, will be applied for the same purpose in an environmental sample. One system of interest to environmental engineers and scientists is the anaerobic digester sludge used to treat wastewater solids. Of particular interest is the growth of the methanogens that are responsible for the production of methane. In order to investigate the specific growth rates of these archaeal microorganisms, a series of bench-scale anaerobic digesters will be operated at hydraulic retention times of 10, 15, and 20 days. After reaching steady daily biogas production, the sludge will be subjected to chloramphenicol treatment and a time series of samples collected for analysis using RT-RiboSyn. The samples will also have increased levels of acetate in order to stimulate the growth of methanogens. It has been long accepted that methanogens grow at low specific growth rates. This work will determine if there is a significant difference in specific growth rate due to different organic loading rates.