Methanogenic Sarcina from an Anaerobic Microbial Community Degrading p-Toluene Sulfonate

The methanogenic strain MM isolated from an anaerobic microbial community degrading p-toluene sulfonate showed optimal values of temperature and pH for growth equal to 37°C and 6.3–6.9, respectively. The doubling times of the isolate grown on methanol, acetate, and methylamines under the optimal conditions were 8.8, 19.1, and 10.3–28.1 h, respectively. The growth of strain MM was observed only when the cultivation medium contained casamino acids or p-toluene sulfonate. The G+C content of the DNA of the isolate was 40.3 mol %. This, together with DNA–DNA hybridization data, allowed the new isolate to be identified as a strain of the species Methanosarcina mazei. The new isolate differed from the known representatives of this species in that it was resistant to alkylbenzene sulfonates and able to demethylate p-toluene sulfonate when grown on acetate.