Conclusions
The results of this research showed that sweet stem sorghum
juice could be employed for fuel ethanol production by batch
VHG fermentation. The nitrogen source has important influence
on ethanol production by S. cerevisiae under anaerobic
conditions. Urea has potential as a nitrogen source to increase
the profitability of fuel alcohol production from concentrated
sweet sorghum juice. Urea, used as nitrogen source, not only
promoted the specific growth rate and ability of ethanol
tolerance, but also increased the ethanol yield and reduced
the formation of byproducts. It is concluded that urea is
a preferred nitrogen source during ethanol fermentation from
concentrated sweet sorghum juice.