単細胞耐塩性シアノバクテリアにおけるCCCPおよびDCMUによる水素産生への影響
A unicellular halotolerant cyanobacterium capable of dark fermentative H2 production generates minimal H2 under illumination, partly because photosystem II-derived oxygen suppresses bidirectional hydrogenase activity. This study examined how the photosystem II inhibitors CCCP and DCMU affect H2 output under both light and dark conditions. Under illumination, both inhibitors elevated H2 photoproduction rates to three-to-five times those of untreated cells. Peak photoproduction rates of 2.26 ± 0.24 and 3.63 ± 0.26 μmol H2/g dry weight/h were recorded with 0.5 μM CCCP and 50 μM DCMU, respectively. In darkness, only CCCP enhanced H2 output, reaching 39.50 ± 2.13 μmol H2/g dry weight/h after 2 h, attributable to its role as an uncoupler of oxidative phosphorylation that elevates respiration and further depletes O2. DCMU, by contrast, reduced the respiration rate. Both inhibitors suppressed chlorophyll fluorescence and lowered O2 levels under light, thereby relieving hydrogenase inhibition.
CCCP uncouples oxidative phosphorylation to increase respiration rate, while DCMU directly blocks photosystem II water-splitting; both mechanisms reduce intracellular O2 concentration, thereby relieving O2-mediated inhibition of bidirectional hydrogenase and enhancing H2 production.
This is basic research at the cellular or molecular level. For human application, inhalation is the most promising delivery route, but inhalation carries explosion risk and concentration matters (empirical LFL of 10%; high-concentration devices are not recommended).
See also:
https://h2-papers.org/en/papers/31346323