This study investigated the effects of constant pH (pH 6–8) on
the biogas production and microbial community during the anaerobic
fermentation of p manure. A pH adjusted to 7.0 enhanced the
biogas production of methanogens and their consumption of organic carbon, and this process was dominated by Methanocorpusulum. At pH 6.0 and 8.0, the detected dominant archaea belonged to Methanosarcina. Therefore, the dominant functional methanogenesis communities and the methanogenesis pathway were varied under different pH conditions. The mechanism of ammonia-inhibition and its relationship between pH were still needed in the further studies.