Alcohol content was
analyzed by an Ebulliometer and compared with
an alcohol hydrometer, while pH was measured
with a pH meter, model JENWAY 3510, UK. The
microstructure of A. aceti WK on the surface of
the loofa sponge in the fermenting broth was
examined using a scanning electron microscope
(SEM). Samples were vacuum dried and then
sputtered with gold and photographed. Each image
was taken on a JEOL JSM-5410LV (JEOL, Tokyo)
scanning electron microscope. The dissolved
oxygen (DO) was measured by an Oxygen
Amplifier Model 170 and reported in term of the
percentage of air saturation. The acidification rate
was defined as the increase in acetic acid
concentration (AAc) during fermentation and
expressed in terms of %/h.