Abstract

Collected Acetic acid producing bacteria from the vinagar sample in some areas around Hồ Chí Minh city and some neighboring provinces have been isolated. A total of 12 strains of Acetic acid forming bacteria have been identified as Acetobacter.sp (A1,A2....,A12) and Gluconobacter.spg. (G9, or Gluc.sp9). The cultural of Acet.spy and Gluc.spg were inoculated into a medium consisting of 5% ethanol, (NH4)2SO4, KH2PO4 at 30°C for 8-10 days. The samples were found to have relatively low total acid concentrations: 2,78% and 2,89%, respectively. Mixing the wine of fruits as from bananas (containing 9% ethanol), grapes (containing 10% ethanol), cherries (9% ethanol) a ratio of 20% (v/v) with the above samples at 30°C, it has been found that after 8 to 10 days the grape vinegar has the highest degree of limpidity with most flavor and a total percentage of acid of 2,88% and 3,04%, respectively. In addition, with grape juice (1kg/10 1 of water), and ethanol added at intevals (5%, then 2,5%, and 2,0%,...) the over all acid concentration in vinegar sample reach 5,8% and 6,3% in 22 days (under static fermentation).