Fig. 7
Growth of Chlamydomonas cultures following the H2 production phase and a second round of H2 production induced by dark anaerobic incubation in HS medium. a Culture growth in HS medium bubbled with sterile air containing 1% CO2, as determined by measuring optical density at 720 nm, following the first round of H2 production. During the growth phase, no O2 absorbent was present, only during the preceding H2 production phase. b, c H2 production and O2 accumulation in cultures subjected to a second round of dark anaerobic incubation in the presence and absence of an iron-salt-based O2 absorbent. The cultures were flushed every 24 h with N2 after determining the gas concentrations in the headspaces of the sealed bottles. Mean values (± SEM) are each based on 4 biological replicates. Statistical significance levels are presented relative to the Chlamydomonas culture subjected to dark anaerobic incubation in HS medium without O2 absorbent as ***p < 0.001