Acetobacter malorum

Genus/species (aliases): Acetobacter malorum (A. pasteurianus)

Gram Stain: Negative


Morphology:

  • Cell: Ellipsoidal 0.9 x 1.1-1.3um, singly or in pairs
  • Colony: Beige, round, regular to waxy, convex and smooth, 0.5mm diameter
  • Liquid Growth: Zoogleal film


Physiological Traits:

Metabolizes ethanol, glycerol, lactate, acetic acid to CO2 and H2O; in low O2 produces acetaldehyde and ethyl acetate; can assimiliate 2-keto-D-gluconic acid.


Ecological Traits:

Isolated from rotting apples in Ghent, Belgium and described in 2002


Distinguishing Features:

Combination of growth on methanol as Carbon source, the ability to use NH4+ as a Nitrogen source when using ethanol as a Carbon source, and the ability to grow on 30% (w/v) D-glucose distinguishes this species from other Acetobacter.


Role in wine:

Isolated rarely from wine; can be found on grape surfaces

Sensitivities in the genus Acetobacter:

  • SO2: +100ppm total SO2
  • Sorbate: 0
  • DMDC: 30-400 mg/L
  • pH: 6.3
  • Acids:
  • Ethanol: >15%
  • Anaerobiosis: VBNC state w/o O2
  • Heat: 35°C


References: 

Cleenwerck et al. Re-examination of Genus Acetobacter with descriptions of Acetobacter cerevisiae sp. nov. and Acetobacter malorum sp. nov. Society for General Microbiology 2002.