In a microbial fuel cell, the transgenic microbes have {HEAD ~ access} to {TAIL ~ a feedstock} 
to
In a microbial fuel cell , the transgenic microbes have { HEAD ~ access } to { TAIL ~ a feedstock }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL