PRODUCTION OF VINEGAR WITH HIGH ACIDITY B Y MODIFIED SUBMERGED CULTURE

In order to produce vinegar with super high acidity (acetic acid conce ntration more than 20 w/v %), cultivation conditions with Acetobacter polyoxogenes, which has been adopted for production of vinegar with hi gh acidity (acetic acid 15 w/v%), was improved. It was concluded that a fed batch culture method was favourable to raise the final acidity o f vinegar. However, high acetic acid concentration considerably inhibi ted the growth of the bacteria and their acetic acid productivity. It was supposed that a theoretical final acidity might reach 23 w/v%, if the extent of inhibition by acetic acid was kept as that of 15 w/v% ac idity. In practice, we succeeded to produce the vinegar with super hig h acidity (21.75 w/v%) by the programmed temperature cultivation metho d, comprised of two stages. In the first stage, incubation temperature was kept at 28-29 degrees C until acidity reached 12 w/v% level, then , in the second stage, the temperature was let down gradually to 15 de grees C with higher acidity.