Enhanced hydrogen production through co-cultivation of Chlamydomonas reinhardtii CC-503 and a facultative autotrophic sulfide-oxidizing bacterium under sulfurated conditions

Abstract

Photoproduction of H2 using microalgae has been considered as a promising approach for developing sustainable hydrogen energy. The algae C. reinhardtii CC-503 was co-cultured with a facultative autotroph sulfur-oxidizing bacterium Thuomonas intermedia BCRC 17547 to improve H2 production. The maximum H2 production of co-culture at sulfur deficiency conditions was 122 μmol/mg Chl with algae/bacteria ratio as 60:1, which was 2.8-fold higher than that of the pure algal culture. Na2S2O3 treatment can result in a maximum H2 photoproduction rate of 255 μmol/mg Chl, which was 5.9 and 2.1 times higher than those of pure algae culture and co-culture without Na2S2O3. Co-cultivation under sulphate condition can also significantly increase the biomass, respiratory rate, starch content and hydrogenase activity of C. reinhardtii. By supplement of Na2S2O3, persistent (52 days) H2 production of bacteria/algae co-culture can be achieved. Our results demonstrated that co-culture of C. reinhardtii CC-503 and bacteria BCRC17547 is a cost-effective strategy for improving photobiological H2 production.