Physiological stratification in electricity-producing biofilms of Geobacter sulfurreducens

GERMÁN DAVID SCHROTT; ORDOÑEZ MARÍA VICTORIA; LUCIANA ROBUSCHI; JUAN PABLO BUSALMEN

CHEMSUSCHEM

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2014 vol. 7 p. 598 - 603

1864-5631

Elucidating  mechanisms  and  limitations  in  electrode  respiration  by electro-active  biofilms  is  significant  for  the  development  of  rapidly emerging  clean  energy  production  and  wastewater  treatment technologies. In Geobacter sulfurreducens biofilms, controlling steps in  current  production  are  thought  to  be  at  the  metabolic  activity  of cells but still remain to be determined. By quantifying DNA, RNA and protein  contents  during  long  term  growth  of  biofilms  on  polarized graphite  electrodes,  we  show  in  this  work  that  current  production becomes  independent  of  DNA  accumulation  immediately  after maximal  current  is  achieved.  Indeed,  the  mean  respiratory  rate  of biofilms rapidly decreases after this point, indicating the progressive accumulation of cells that do not contribute to current production, or contribute  to  a  negligible  extent.  These  results  support  the occurrence  of  physiological  stratification  within  biofilms,  as  a consequence  of  respiratory  limitations  imposed  by  limited  biofilm conductivity.