Simazine Enhances Dark Fermentative H Production by Unicellular Halotolerant Cyanobacterium .

The halotolerant cyanobacterium is a potential H producer that induces H evolution under nitrogen deprivation. H is mainly produced the catabolism of stored glycogen under dark anaerobic condition. H evolution is catalyzed by O-sensitive bidirectional hydrogenase. The aim of this study was to improve H production by using various kinds of inhibitors. Among all types of inhibitors, simazine efficiently promoted the highest H production under dark conditions. High simazine concentration and long-term incubation resulted in a decrease in cell and chlorophyll concentrations. The optimal simazine concentration for H production by was 25 µM. Simazine inhibited photosynthetic O evolution but promoted dark respiration, resulting in a decrease in O level. Hence, the bidirectional hydrogenase activity and H production was increased. showed the highest H production rate at 58.88 ± 0.22 µmol H g dry weight h and H accumulation at 356.21 ± 6.04 μmol H g dry weight after treatment with 25 µM simazine under dark anaerobic condition for 2 and 24 h, respectively. This study demonstrates the potential of simazine for the enhancement of dark fermentative H production by .