For example, systems can use feedstock materials, such as {HEAD ~ cellulosic} and lignocellulosic materials and starchy or sugary materials, to produce ethanol and {TAIL ~ butanol}, e.g., by fermentation 
to produce
For example , systems can use feedstock materials , such as { HEAD ~ cellulosic } and lignocellulosic materials and starchy or sugary materials , to produce ethanol and { TAIL ~ butanol } , e.g. , by fermentation
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH