<P><B>Abstract</B></P> <P>The aim of this work is to investigate the hydrogen and poly-β-hydroxybutyrate (PHB) production during the photofermentative treatment of the effluent from a dark fermentation reactor fed with the organic fraction of municipal solid waste. Two different inocula, an adapted culture of <I>Rhodobacter sphaeroides</I> AV1b and a mixed consortium of purple non sulphur bacteria have been investigated under the same operational conditions. Different hydrogen productivities of 364 and 559NmL H<SUB>2</SUB> L<SUP>−1</SUP> were observed for the <I>Rhodobacter sphaeroides</I> and the mixed culture consortium tests, respectively: the consortium of PNSB resulted 1.5-fold more productive than the pure culture. On the other hand, <I>Rhodobacter sphaeroides</I> culture showed a higher PHB productivity (155mg PHB g COD<SUP>−1</SUP>) than the mixed culture (55mg PHB g COD<SUP>−1</SUP>). In all the tests, the concomitant H<SUB>2</SUB> and PHB production was associated to a dissolved COD removal higher than 80%.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Photofermentative treatment of a dark fermentation effluent is investigated. </LI> <LI> Performances of a <I>R. sphaeroides</I> and a mixed PNSB culture are compared. </LI> <LI> The mixed culture results more efficient in H<SUB>2</SUB> production (233.8NmL H<SUB>2</SUB> g COD<SUP>−1</SUP>). </LI> <LI> The pure culture shows a higher PHB productivity (155mg PHB g COD<SUP>−1</SUP>). </LI> <LI> High soluble COD removal from DFE is achieved (>80%). </LI> </UL> </P>