For example, systems can use feedstock materials, such as {HEAD ~ cellulosic} and lignocellulosic materials and starchy or sugary materials, to produce {TAIL ~ ethanol} and 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 { TAIL ~ ethanol } and 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 TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH