T. Roukas, CONTINUOUS ETHANOL-PRODUCTION FROM CAROB POD EXTRACT BY IMMOBILIZED SACCHAROMYCES-CEREVISIAE IN A PACKED-BED REACTOR, Journal of chemical technology and biotechnology, 59(4), 1994, pp. 387-393
The continuous production of ethanol from carob pod extract by immobil
ized Saccharomyces cerevisiae in a packed-bed reactor has been investi
gated. At a substrate concentration of 150 g dm-3, maximum ethanol pro
ductivity of 16 g dm-3 h-1 was obtained at D = 0.4 h-1 with 62.3% of t
heoretical yield and 83.6% sugars' utilization. At a dilution rate of
0.1 h-1, optimal ethanol productivity was achieved in the pH range 3.5
-5.5, temperature range 30-35-degrees-C and initial sugar concentratio
n of 200 g dm-3. Maximum ethanol productivity of 24.5 g dm-3 h-1 was o
btained at D = 0.5 h-1 with 58.8% of theoretical yield and 85% sugars'
utilization when non-sterilized carob pod extract containing 200 g dm
-3 total sugars was used as feed material. The bioreactor system was o
perated at a constant dilution rate of 0.5 h-1 for 30 days without los
s of the original immobilized yeast activity. In this case, the averag
e ethanol productivity, ethanol yield (% of theoretical) and sugars' u
tilization were 25 g dm-3 h-1, 58.8% and 85.5%, respectively.