Enzymatic hydrolysis of potato starch and ethanol production

Abstract

The hydrolysis of potato starch using one (Termamyl or Fungamyl) and two combined (Termamyl and Supersan) commercial enzyme preparations and ethanol production from the hydrolysates obtained using the yeast Saccharomyces cerevisiae were studied. Potato tubers were previously prepared as mash or flour. The study dealt with the effects of the hydromodulus (1:1 and 1:0.5), particle size (0.1, 0.2 and 0.4 mm) as well as the type and concentration of enzyme on the enzymatic hydrolysis of potato starch. The highest dextrose equivalent (79.3%, DE) was achieved during two-enzyme hydrolysis (combination of two enzyme preparations: Termamyl 14.4 KNU/dm3 and Supersan 28.8 AGU/dm3) of starch from potato flour (particle size: 0.1-0.2 mm) at an inital starch concentration of 75 g/dm3. During the two-enzyme hydrolysis, a lower DE (61%) was achieved when potato mash was used as a starch source. Using Termamyl (14,4 KNU/dm3) and potato mash a higher DE was achieved at the hydromodulus 1:1 (51.2%) than at the hydromodulus 1:0.5 (40.9%). The highest ethanol concentration (5.0 vol%) was obtained when the hydrolyzate of potato flour from the two-enzyme process was used as a substrate for alcoholic fermentation.