| Summary: | The purpose of this research was to determine the diversity of methane oxidizing
bacteria (MOB) and their ability to oxidize methane gasses in rice fields that have been
given various treatments (salinity, carbon source, and fertilizer). The rice variety used in this research was the Ciherang rice with a total number of 39 pots. The planting media was measured for its physiochemical parameters using a pH meter. When the rice reaches 2 weeks and 12 weeks of age, an in situ methane gauging was performed using a Detector. The MOB isolation processes were carried out using culture dependent and culture independent methods. Culture independent isolation was performed by totally isolating soil bacteria DNA on each treatment, and then the MOB presence was tested using a pmoA gene detection. The result of pmoA gene amplification was then analyzed using the DGGE to determine the MOB diversity. Culture dependent isolation was performed to obtain MOB isolates. MOB consortium was tested for its oxidation capacity by using GC. The found isolates were then isolated of their bacteria DNA and then amplified using pmoA gene, mxa and 16S rRNA. Isolates that were positively detected having the said gene were subjected to a generic assignment process and a 16 rRNA gene sequencing. The results of this research shows that MOB in rice fields that have been given different treatments of fertilizer, salinity and carbon source have different community structures. Rice plants before bearing grains show higher methaneemission than when bearing grains. The reduction of methane emission on NPK fertilizer treatment shows higher value compared with the bioactivator. On substrate source treatment, the methane emission reduction was highest on rice-straw-added compost plant media treatment. Both strains (AP37 and AP41) have pmoA and mxa functional genes. AP37 strain was strongly suspected as a member of the Pantoea genus, while AP41 strain was strongly suspected as a member of the Ralstonia.
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