Multi-Stage Microbial System for Continuous Hydrogen Production

A method using sequential chemostat culture vessels to provide continuous H2 production, in which photosynthetic O2 evolution and H2 photoproduction are separated physically into two separate bioreactors, comprising: a) growing a microorganism culture able to continuously generate H2 by photosynthetically producing cells at about the early-to-late log state in a first photobioreactor operating asa sulfur chemostat under aerobic and/or conditions; b) continuously feeding cells from the first photobioreactor to a second photobioreactor operating under anaerobic conditions and sulfur deprivation conditions resulting from constant uptake of sulfate in the first bioreactor and a low rate of culture flow between the first and second bioreactors, for induction of hydrogenase and H2photoproduction to allow for continuous cultivation of the microorganism's cells in the first photobioreactor and constant H2 production in the second photobioreactor, and c) H2 gas from the second bioreactor.