K. Matsuura et al., ACCELERATION OF CELL-GROWTH AND ESTER FORMATION BY ULTRASONIC WAVE IRRADIATION, Journal of fermentation and bioengineering, 77(1), 1994, pp. 36-40
The effects of ultrasonic wave irradiation on cell growth and the form
ation of ethanol and other volatile components in the fermentation pro
cess were investigated. The fermentation periods were reduced to 50-64
% in wine, beer, and sake made from saccharified rice solution when we
ak ultrasonic waves were irradiated at 30 nW/cm2; the total intensity
was 590 mW. YEPD medium fermented by a combination of optimal thermal
trajectory control and continuous ultrasonic irradiation yielded a con
centration of isoamylacetate about 2.5 times greater than the maximum
concentration under isothermal conditions (20-degrees-C). Irradiation
had virtually no effect when the dissolved carbon dioxide concentratio
n (DCO2) was maintained at a level lower than the experimental value o
f Bunsen's CO2 absorption coefficient. Therefore, it is suggested that
irradiation accelerates the formation of ethanol and other components
mainly by decreasing DCO2.