PURPOSE: To provide a novel microbial strain, Acetobacter altoacetigenes, requiring acetic acid as a component of culture medium at a concentration higher than a specific level, capable of proliferating in an acidic condition of lower than a specific pH level, and capable of producing white vinegar having excellent taste and flavor at a high acetic acid concentration in high efficiency.
CONSTITUTION: A soft agar medium [medium (a)] composed of yeast extract, polypeptone, glucose, acetic acid, ethanol and agar is prepared beforehand. The concentrations of acetic acid and agar in the medium are 6.5W/V% and 0.5W/ V%, respectively. The medium (a) is coated with thin layer of a medium (b) having the same composition as the medium (a) provided that the agar concentration is 1W/V%. An unrefined vinegar is smeared to the surface of the obtained agar plate medium, and cultured at 90W100%RH and 30°C for 7W30 days to form colonies of the bacteria. The titled novel bacterial strain can be separated by repeating the separation of the colonies. A representative strain of the bacteria is Acetobacter altoacetigenes MH-24 (FERMBP No.491). It is essential to select the acetic acid concentration and pH of the above medium to ≥4W/V% and ≤3.5.
FUJIYAMA SEIICHI
OOMORI SHIYOUJI
MASAI HIROSHI
