Improvement of Hydrogen Production by Immobilized Rhodopseudomonas palustris CGA009 Using Reverse Micelles as Microreactor
A. Singh, K. Misra
Rice University, US
Keywords: rhodopseudomonas palustris CGA009, reverse micelles, AOT, biological hydrogen production
Abstract:Within the process of photobiological hydrogen production, purple non-sulfur (PNS) bacteria are an interesting subject of study because of their high substrate conversion efficiencies and their capability of using a wide variety of substrates either for growth or hydrogen production. Reverse micelles provide us a unique immobilization technique to enhance the biological hydrogen production of PNS bacteria and have shown encouraging results. In the present study, the PNS bacterium Rhodopseudomonas palustris CGA009 has been immobilized separately in an aqueous pool of the reverse micelles fabricated by various surfactants (AOT, CBAC and SDS) and apolar organic solvents (benzene and isooctane). All reverse micellar systems of coupled bacterial cultures gave encouraging hydrogen production (rate as well as yield) compared to the aqueous culture. An average of 50 fold increased hydrogen production rate was observed in case of AOT/H2O/isooctane reverse micellar system as compared to the aqueous culture. CBAC/H2O/isooctane reverse micellar system is used for the first time for hydrogen production and is as promising as AOT/H2O/isooctane reverse micellar system. All these reverse micellar systems were also screened to reduce the inhibitory effect of NH4+ on hydrogen production. Optimal hydrogen production was observed at 37°C temperature, 600 lx light intensity and 7 pH.