초록
<P><B>Abstract</B></P> <P>Biohydrogen production from cellulose by a bacterial co-culture is a potentially promising approach for producing bioenergy from a low cost substrate. The use of a cellulolytic bacterium, <I>Cellulomonas fimi</I>, permits cellulose conversion and the in situ production of substrate for growth and hydrogen production by the photosynthetic bacterium <I>Rhodopseudomonas palustris</I>. Response surface methodology (RSM) with a Box-Behnken design (BBD) was used to examine variations in the key parameters: substrate (cellulose) concentration, yeast extract concentration and the microorganism ratio (<I>Rps. palustris/C. fimi</I>). For the co-culture of <I>R. palustris</I> and <I>C. fimi</I> the highest hydrogen production (44 mmol H<SUB>2</SUB>/L) was achieved at the highest substrate concentration (5 g/L); however, the highest hydrogen yield (3.84 mol H<SUB>2</SUB>/mol glucose equivalent) was observed at the lowest cellulose concentration and highest microorganism ratio. High COD removal efficiencies, over 70%, were achieved over a wide range of conditions and were positively affected by the concentration of yeast extract.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effective H<SUB>2</SUB> production from cellulose by co-cultures without previous pre-treatment. </LI> <LI> Substrate concentration affects differently hydrogen yield and production. </LI> <LI> Maximum yield at lowest cellulose concentration and highest microorganism ratio. </LI> <LI> Microorganism ratio manipulated to increase cellulose breakdown and decrease photo-fermentation imbalance. </LI> </UL> </P>