{TAIL ~ Microbes} may obtain energy from a feedstock or {HEAD ~ material} through a metabolic process 
{ TAIL ~ Microbes } may obtain energy from a feedstock or { HEAD ~ material } through a metabolic process
TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH