Cloning and characterization of the dnaKJ operon in Acetobacter aceti

The dnaKJ operon of Acetobacter aceti was cloned and sequenced. The profile of the gene configuration was similar to that of other α-proteobacteria. In the DnaK and DnaJ proteins of A. aceti, the characteristic domains/motifs reported in other organisms were well conserved. This operon was transcribed in response to a temperature shift and exposure to ethanol/acetic acid. The overexpression of this operon in A. aceti resulted in improved growth compared to the control strain at high temperature or in the presence of ethanol, suggesting a correlation to resistance against stressors present during fermentation, although the overexpression did not increase the resistance to acetic acid.