Isolation and Characterization of Acetoacetic Bacteria from Decomposed Fruits

Acetic Acid Bacteria (AAB) are rod shaped, aerobic, and gram-negative bacteria. These have ability to oxidize ethanol to acetic acid and are used in vinegar production.The aim of this study was to isolate and identify the acetic acid bacteria which are capable of growing at 30-40oC, temperature generally prevalent in this area for most of the year. Microorganisms were isolated from decomposed fruits like banana, pear, and orange obtained from local vegetable market. We used specific culture media viz.isolation, enrichment and peptone agar media. The samples were inoculated in sterilized GYC standard media and then incubated at 30°C for 48 hours. Successive subculture was performed to screen out the strains. In Gram’s staining, the morphology of the isolated bacteria exhibited pink and rod shaped. Various biochemical tests of the isolated strain like starch hydrolysis,methyl red,and ketogenesiswere positive, while starch hydrolysis and cellulose test were negative which revealed that the strain isolated from decomposed fruits were acetic acid bacteria. The study indicated that all the strains grew well at pH 5-6 and temperature28oCto30oC.