Samples of 5 mL (from the first and last day) were frozenat 20 C until DNA extraction was conducted. DNA was isolatedfrom the samples using the FastDNA SPIN Kit for soil (MP Biomedicals)according to the protocol provided by the manufacturer. DNA was stored 20 c after the isolation until qPCR methodwas performed using one mL of extracted DNA samples. DNA waseluted in 500 mL milli-Q water. Eight primer sets (Table 3) wereused for isolation of the 16S rRNA gene sequences of the followingmicroorganisms: the order of Methanobacteriales, Methanococcalesand Methanomicrobiales, the families Methanosarcinaceaeand Methanosaetaceae, as well as the total bacteriaand archaea according to the experimental procedures followed byYu