Prolongation of H sub(2) photoproduction by immobilized, sulfur-limited Chlamydomonas reinhardtii cultures

Two approaches to prolong the duration of hydrogen production by immobilized, sulfur-limited Chlamydomonas reinhardtii cells are examined. The results demonstrate that continuous H sub(2) photoproduction can occur for at least 90 days under constant flow of TAP medium containing micromolar sulfate concentrations. Furthermore, it is also possible to prolong the duration of H sub(2) production by cycling immobilized cells between minus and plus sulfate conditions.