Characterization of Methanosarcina mazei N2M9705 isolated from an aquaculture fishpond

A new methanogenic isolate, designated as strain N2M9705 (=OCM 668), was is olated from an aquaculture fishpond near Wang-gong, Taiwan. This strain gre w on trimethylamine and methanol, but it did not catabolize H-2-CO2, acetat e, or formate. The cells were stained Gram-negative, nonmotile, irregular c occus 0.6-0.8 mu m in diameter. Gas vacuoles were observed and cell aggrega ted to form various sizes of granules. Cells grew optimally at 32 degrees-3 7 degrees C with 1% NaCl. The pH range of growth was 6.2-7.4, and higher pH inhibited the cell growth. The cells grew well in minimal medium, but grow th was greatly stimulated by yeast extract and peptone. A comparison of 16S rDNA sequences of this organism phylogenetically related to Methanosarcina mazei. This is the first report of methyltrophic methanogenic isolated fro m an aquaculture fishpond.