ABSTRACT

The aim of this study was to isolate and characterize AAB are an important and diverse group of bacteria involved in the production of fermented foods and beverages, especially known for their production of acetic acid (ethanoic. acid) in the making of vinegar from different samples of protein waste products collected from Umudike, Umuahia. In this study, isolates from protein wastes were characterized to identify acetic acid bacteria. Glucose yeast extract media supplemented with CaCO3(GYC) was used for the isolation of the bacteria. Twenty-five (25) (white, creamy and yellow pale colored) well isolated colonies were selected to be analyzed. Out of 25 isolates, fourteen (14) were suspected to be acetic acid bacteria because they produced clear zones around their colonies in the selective GYC culture medium. Out of the 14 analyzed isolates, six (6) were Gram negative rod. Presumptive identification of the acetic acid bacterial isolates included Acetobacter acetii and Gluconobacter oxidans. Morphologically identified and biochemically confirmed acetic acid bacterial isolates were then further checked for their abilities to produce acetic acid by titration in YGEA (Yeast, Glucose, Ethanol, Acetic acid) medium. Acetic acid production rate varied among the isolates. Among 3 acetic acid producing strains, isolate from fish 2 showed the highest acetic acid production (24.34 g/lOOml) rate at 37°C while those from milk 1 and meat 2 showed 23.96 g/100ml and 23.46 g/100ml respectively. Although 3 isolated and identified bacteria were fulfilling AAB characteristics, preliminary identification was not sufficient to conclude that AAB was found, further molecular identification study was recommended in order to confirm and determine which genera of AAB are found in these waste products.