Comparison of enzymatic (E-Mill) and conventional dry-grind corn processes using a granular starch hydrolyzing enzyme

A new low temperature liquefaction and saccharification enzyme STARGEN 001 (Genencor International, Palo Alto, CA) with high granular starch hydrolyzing activity was used in enzymatic dry-grind corn process to improve recovery of germ and pericarp fiber before fermentation. Enzymatic dry-grind corn process was compared with conventional dry-grind corn process using STARGEN 001 with same process parameters of dry solid content, pH, temperature, enzyme and yeast usage, and time. Sugar, ethanol, glycerol and organic acid profiles, fermentation rate, ethanol and coproducts yields were investigated. Final ethanol concentration of enzymatic dry-grind corn process was 15.5 ± 0.2% (v/v), which was 9.2% higher than conventional process. Fermentation rate was also higher for enzymatic dry-grind corn process. Ethanol yields of enzymatic and conventional dry-grind corn processes were 0.395 ± 0.006 and 0.417 ± 0.002 L/kg (2.65 ± 0.04 and 2.80 ± 0.01 gal/bu), respectively. Three additional coproducts, germ 8.0 ± 0.4% (db), pericarp fiber 7.7 ± 0.4% (db), and endosperm fiber 5.2 ± 0.6% (db) were produced in addition to DDGS with enzymatic dry-grind corn process. DDGS generated from enzymatic dry-grind corn process was 66% less than conventional process.