Isolation of acetic acid bacteria from honey

Four thermotolerant acetic acid bacteria designated as CMU1, CMU2, CMU3 and CMU4 were isolated from six honey samples produced by three native bee species in northern Thailand, namely the dwarf honey bee (Apis florea), Asian honey bee (A. cerena) and giant honey bee (A. dorsata). All isolates were tested for their tolerance to acetic acid and ethanol at 30 degrees C and 37 degrees C. It was found that they grew only in a medium containing 1% (v/v) acetic acid at 30 degrees C. However, isolate CMU4 showed the highest toleration to ethanol, viz. 10% (v/v) and 9% (v/v) at 30 degrees C and 37 degrees C respectively. Morphological and biochemical examination indicated that all isolates were members of the genus Gluconobacter.