transcriptomics of feast-famine reactors
Overall, the results of the DNA and RNA analysis showed that Methylocystis was the most active bacterial genus and represented more than 65% of the methanotrophic population in all the conditions tested. Together with MOB, the most represented metabolisms were denitrification and nitrification. Nitrite was used either as an electron donor or acceptor, which helpeding to detoxify the systems. The feast regimes encouraged the methane degradation activity through the higher expression of genes related to methane oxidation as a result of the most active Methylocystis population. In the reactors acclimated for one year to feast-famine cycles (STR2), the metabolism of PHBs was more active in famine. This shows that the methanotrophs may rely on an endogenous storage compound, such as PHB, as a co-substrate to maintain cell viability, while methane was not present. Overall, this study showed that there is an emergence and resilience of methanotrophic activity that can be applied to the operation of bioreactors subjected to the treatment of methane diffuse and dilute emissions.