Isolation, Screening, and Characterization of Methane-Utilizing Bacteria From the Sediment of Lowland Rice

Abstract

Methane is a major greenhouse gas that contributes to climate change. Methanogen and methanotrophic group microbes play a role in methane emissions in lowland rice fields. Methane is produced by methanogenic bacteria that decompose organic matter in anaerobic conditions. These bacteria will be active if the soil is inundated for an extended period of time. Some of this methane will be oxidized by methanotrophic bacteria in the rhizosphere. The researchers aimed to isolate, screen, and characterize methane-utilizing bacteria in lowland rice sediment from several Indonesian provinces. 27 methane- utilizing bacteria were isolated from rice field sediments in Lampung, West Java, and East Nusa Tenggara Province. Six of them had the potential to reduce methane emissions by more than half. A pmoA-like gene could be found in all of the selected isolates. The bacterial isolates were identified as Mycobacterium senegalense, Bacillus marisflavi, Bacillus methylotrophicus, Flavobacterium tirrenicum, Providencia stuartii, and Rhizobium rhizoryzae after characterization and identification with the Biolog OmniLog® ID system. These were all capable of nitrogen fixation, phosphorus solubilization, and IAA production. These isolates have the potential to be used as biofertilizers and methane mitigation agents. Keywords: biofertilizers, greenhouse gas, lowland rice, methane-utilizing bacteria