THE ETHANOLIC FERMENTATION OF SOLUTIONS O F D-XYLOSE BY PACHYSOLEN-TANNOPHILUS - THE INFLUENCE OF AERATION RATE

In this work, it is studied the influence of aeration rate in the disc ontinuous fermentation of D-xylose solutions by Pachysolen tannophilus (ATCC 32691). The aeration rate has been modified in the interval 0 v /v/min (it is only supplied the air that comes into the agitation vort ex) and 0.300 v/v/min, maintaining a constant temperature of 30 degree s C and using a culture broth with an initial pH of 3.5. From the expr imental results it is deduced that the best aeration rate, in view of the ethanol production, is that where it is only supplied the air that comes into the agitation vortex. Under these conditions, the maximum specific growth rate is 0.25h(-1), the total biomass yield 0.12 (kg bi omass).(kg D-xylose)(-1), the ethanol production specific rate 0.05 (k g ethanol).(kg biomass)(-1). h(-1) and the ethanol total yield 0.33 (k g ethanol).(kg D-xylose)(-1).