Acetobacter cerevisiae

Genus/Species: Acetobacter cerevisiae

 

Gram Stain: Negative

Morphology:

  • Cell: ellipsoidal to rod-shaped, cells occurring singly, in pairs, or occasionally in short chains
  • Colonies: Beige to brown, round, regular to wavy, raised and smoothe
  • Liquid growth:

Physical traits:

  • Growth substrates: Glucose, ethanol, organic acids, glycerol
  • Metabolic end products: acetaldehyde, ethyl acetate, dihydroxyacetone, gluconic acid
  • This organism is an obligate aerobe

Ecological traits:

Spoiled and unspoiled fruit, isolated from beer

Distinguishing traits:

Oxidase-negative, catalase-positive, 2-keto-D-gluconic acid produced from D-glucose, 5-keto-D-gluconic acid is not produced from D-glucose, no growth with ammonia as the sole nitrogen source on ethanol as carbon source, no growth as maltose or methanol as carbon source.

Role in wine:

 Spoilage organism converting ethanol to acetic acid

Sensitivities:

 Sensitive to very  low pH but can grow at wine pH; can survive at low oxygen levels, optimum temperature 20-25˚C, known to withstand ethanol levels as high as 15%