rapid than on the methyl halides and also achieved higher cell densities strain imb 1 was unable to grow without the provision of ammonium salts in the medium table 2______________________________________substrate sup a mebr oxidized mmoles l u03bc h sup 1 sup b y sub m g mol sup 1 pmol 10 sup 6 cells h ______________________________________mebr 0 8 0 03 4 2 1 4mecl 0 8 0 03 3 4 1 7mei 0 3 0 07 2 7 2 4mef 0 4 0 00 0 0 0 0methane 3 7 0 00 0 0 0 0mma 5 0 0 17 nd 1 0dma 4 0 0 19 nd sup c 1 1tma 4 0 0 16 nd 0 8glucose 2 0 0 24 30 0 0 6acetate 5 0 0 24 5 1 0 8______________________________________ sup a mecl mei and mef refer to methyl chloride methyl iodide and methyl fluoride and ma dma and tma refer to mono di and trimethylamine sup b specific growth rate sup c nd not determined cells suspensions readily oxidized 14 c mebr to 14 co 2 after two consecutive transfers in medium in which the growth substrate was not a methyl halide thus the ability of strain imb 1 to oxidize mebr was present regardless of the substrate that was utilized for growth see table 2 above however mebr oxidation rates in methyl halide grown.