Properties of Bacterial Cellulose Produced in Grape Medium by Native Isolate Gluconacetobacter Sp

During the production of grape wine, the
occurrence of thick leathery pellicle at the air-liquid interface
was found as a contaminant. The pellicle produced
was investigated with a view to use as biodegradable
polymer. The bacterium that is responsible for the pellicle
production was isolated, characterized and identified as
Gluconacetobacter sp. Pellicle was produced in pasteurized
grape extract as well as in HS medium by the isolated organism
in static conditions. The purified film was subjected
for Fourier transform infrared spectroscopy and C13
solid NMR spectroscopy analysis, which confirmed the
pellicle to be a cellulosic material. Scanning Electron
Micrograph showed ultra fine network structure along
with cells. The films were tested for its physicomechanical
characters, barrier and thermal properties. The films of 25-
l thickness showed very high tensile strength (41.158
MPa) and elongation of 0.987 mm. The thermal properties
of the films were characterized by Differential scanning
calorimetry and Thermo gravimetric analysis. The melt
peak temperature was found to be 111.65�C. The percentage
of weight loss was found to be 20% at 327.86�C. Barrier
properties (oxygen transmission rate and water vapor
transmission rate), indicated a high oxygen barrier but low
water barrier. This is the first report on the barrier properties
of bacterial cellulose from Gluconacetobacter sp