I recommend you protocol used by Itso 2011 entitled: Identification of a novel acetate-utilizing bacterium belonging to Synergistes group 4 in anaerobic digester sludge. ISME Journal (2011) 5, 1844–1856; doi:10.1038/ismej.2011.59.
Check also: Zehnder AJ, Huser BA, Brock TD, Wuhrmann K. (1980). Characterization of an acetate-decarboxylating, non-hydrogen-oxidizing methane bacterium. Arch Microbiol 124: 1–11.