propionate-fed mesophilic anaerobic chemostats

Propionate is one of the most important intermediates of anaerobic fermentation. Its oxidization performed by syntrophic propionate-oxidizing bacteria (SPOB) is considered as a limited step for methane production. However, the information of SPOB is limited due to the difficulty in pure culture isolation. In this study, two anaerobic chemostats fed with propionate as the sole carbon source were operated at different dilution rates (0.05 d-1 and 0.15 d-1). The propionate- and acetate-oxidizing bacteria in the two methanogenic chemostats were investigated combining DNA-stable isotope probing (DNA-SIP) and 16S rRNA gene high-throughput sequencing.