Separate hydrolysis and fermentation and simultaneous saccharification and fermentation methods in bioethanol production and formation of volatile by-products from selected corn cultivars

Corn (Zea mays L.) is a widely used raw material in the production of bioethanol. Creating new cultivars and applying appropriate fermentation techniques to increase production efficiency is still important for bioethanol producers. The purpose of the study presented here was to evaluate the correlation between differentiators of corn cultivars and fermentation methods in view of the efficiency of bioethanol production. The five selected cultivars differed by FAO (Food and Agriculture Organization) number, type of hybrid cultivar, and type of grain. The tested samples generally showed significant (p < 0.05) differences in starch contents. Ethanol fermentation was investigated using separate hydrolysis and fermentation (SHF) as well as simultaneous saccharification and fermentation (SSF) methods The SSF method proved the most effective for the production of bioethanol, regardless of cultivar. The greatest ethanol yield (p < 0.05) was achieved with the semiflint SM Hetman cultivar (81.23% theoretical value) under the SSF process. A negative correlation (p < 0.05) between starch content and ethanol yield was demonstrated. Chromatographic analysis of the raw spirits showed that lower levels of fermentation by-products were detected for the SSF method than for SHF.