Comparative evaluation of fermentative hydrogen production using Enterobacter cloacae and mixed culture: Effect of Pd (II) ion and phytogenic palladium nanoparticles

•Coriandrum sativum leaf extract was responsible for the formation of PdNPs.•PdNPs improved the hydrogen production from glucose by mixed culture.•Insignificant hydrogen yield by E. cloacae was found by the addition of PdNPs.•PdCl2 showed an inhibitory effect on hydrogen production due the metabolites shift. Palladium nanoparticles (PdNPs) were synthesized from PdCl2 using Coriandrum sativum leaf extract. The transmission electron microscopy (TEM) images confirm that the formation of PdNPs was mainly spherical in shape, with an average size of 87nm. The influence of the PdCl2 and synthesized PdNPs on fermentative hydrogen production from glucose using Enterobacter cloacae and mixed culture was evaluated. In PdCl2 supplemented experiments, the hydrogen yields of E. cloacae and mixed culture were 1.39±0.07 and 2.11±0.11mol H2/mol glucose, respectively, with 5.0mg/L of PdCl2. The resulting hydrogen yield (P