A Selective Medium for the Isolation and Differentiation of Gluconobacter and Acetobacter

ABSTRACT

A new medium permits selective isolation of acetic acid bacteria within 3 days and differentiation between Gluconobacter and Acetobacter within 48 hr. Dextrose Sorbitol Mannitol (DSM) Agar was devised to provide differentiation of Gluconobacter and Acetobacter based on the preferential oxidation of carbon sources. Selectivity is achieved by acidification and the incorporation of cycloheximide to inhibit yeast and mold growth. To minimize interference by other acid tolerant gram positive bacteria, best results were obtained with the addition of 29.5 micrograms of brilliant green or 0.1g of sodium desoxycholate per liter of medium. D.S.M. has been used in our laboratory as both a selective and differential medium in beverage and fermentation quality control procedures.