Physiological Characterization and Molecular Identification of Methanotrophic Bacteria isolated from Ricefields in Bogor and Sukabumi.

Abstract

Methane (CH4) is one of the main greenhouse gasses that could absorb infra-red radiation so it contribute to global warming. Methanotrophs are bacteria that are able to grow using methane as their only source of carbon and energy. They play a major role in the reduction of the release of methane into the atmosphere from environments. Methanotrophic bacteria isolated from Ricefields in Bogor and Sukabumi (BGM 1, BGM 2, BGM 3, BGM 9, and SKM 14) had a high methane oxidation. Activity physiologycal assay using API 20 NE and molecular identification using 16S rRNA gene sequence analysis were conducted in this research. Five isolates showed a positive reaction of physiological assays for gelatine, β-galactosidase enzyme, glucose assimilation, mannitol assimilation, N-asetil-glukosamin assimilation, maltose assimilation, and malic acid assimilation. BGM 1 and BGM 3 16S rRNA sequence showed that they had similarity to Methylocystis rosea into 74% and 70% respectively, while BGM 2 and BGM 9 had similarity to Methylococcus capsulatu into 83% and 85% respectively, and SKM 14 had 65% similarity with Methylobacter sp. Phylogenetic tree showed that BGM 1 and BGM 3 isolates were in the same group with Methylocystis rosea strain SV97T, Methylobacterium extorquens, and Methylosinus trichosporium, nevertheless they were very close related to Methylocystis rosea strain SV97T. BGM 2, BGM 9, and SKM 14 isolates were in the same group with Methylococcus capsulatus strain texas, Methylomicrobium buryatense, and Methylobacter sp. nevertheless BGM 2 and BGM 9 isolates were very close related to Methylococcus capsulatus strain texas. While SKM 14 was very close related with Methylobacter sp.