Zymomonas

Zymomonas is a genus of bacteria. The best known species from this genus is Zymomonas mobilis. Members of this genus are gram negative, anaerobic, non-sporulating, polarly-flagellated, rod-shaped bacteria.

It is a fermenting bacteria that contributes to cider sickness and beer spoilage.

Zymomonas is a bacteria that has a near theoretical ethanol yield from glucose, no oxygen requirement thus negating the need for expensive oxygen transfer, and high ethanol tolerance making it an effective microbe for ethanol biofuel production.

Beer Spoilage
Zymomonas is a waterborn unwanted bacteria in beer, creating an estery/sulfury flavour due to the production of acetaldehyde and hydrogen sulfide. This can be likened to a rotten apple smell or fruity odor. Zymomonas haven't been reported in larger breweries due to the low temperatures (8-12 degrees C) and stringent carbohydrate requirements. The optimum growth temperature is 25-30 degrees C.