The comprehensive analysis of sorghum cultivated in Poland for energy purposes: Separate hydrolysis and fermentation and simultaneous saccharification and fermentation methods and their impact on bioethanol effectiveness and volatile by-products from the grain and the energy potential of sorghum straw.

The aim of this work was to study the potential of sorghum crop cultivated in European climate as an energy material. The investigation showed strong interaction between the fermentation method and the sorghum cultivar. It was also noted that the cultivar with the highest grain yield showed the highest yield of ethanol per hectare, achieving 1269 L/ha in SHF (separate hydrolysis and fermentation) and 1248 L/ha in SSF (simultaneous saccharification and fermentation). Chromatographic analysis of raw spirits showed that smaller amounts of impurities are formed in the SSF process than in the SHF process. The calorific value of sorghum straw was also measured, and amounted to 16,050-16,840 kJ/kg. The results have demonstrated the high value of sorghum as grain for bioethanol production and as straw as a valuable feedstock for forming pellets or briquettes.