Correlation between respiration and hydrogenase adaptation in <i>Scenedesmus obliquus</i>

Francis, K.; Senger, Horst

doi:10.1111/j.1399-3054.1985.tb02377.x

Cited by 4 publications

(1 citation statement)

References 14 publications

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“…Figure 1 schematically shows the functional coordination of chloroplast and mitochondrial electron transport under S-deprivation and H 2 -evolution. Under these conditions, when the activity of photosynthesis is substantially suppressed, mitochondrial respiration is necessary and suYcient to consume the low levels of photosynthetically generated O 2 , causing anaerobiosis in the culture (Kessler 1966;Francis and Senger 1985;Ghirardi et al 2000). Substantial changes in endogenous substrate metabolism and cellular morphological alterations take place during S-deprivation and H 2 -evolution.…”

Section: Temporal Separation Of O 2 -And H 2 -Evolutionmentioning

confidence: 98%

Photosynthetic H2 metabolism in Chlamydomonas reinhardtii (unicellular green algae)

Melis

2007

Planta

253

135

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Unicellular green algae have the ability to operate in two distinctly different environments (aerobic and anaerobic), and to photosynthetically generate molecular hydrogen (H2). A recently developed metabolic protocol in the green alga Chlamydomonas reinhardtii permitted separation of photosynthetic O2-evolution and carbon accumulation from anaerobic consumption of cellular metabolites and concomitant photosynthetic H2-evolution. The H2 evolution process was induced upon sulfate nutrient deprivation of the cells, which reversibly inhibits photosystem-II and O2-evolution in their chloroplast. In the absence of O2, and in order to generate ATP, green algae resorted to anaerobic photosynthetic metabolism, evolved H2 in the light and consumed endogenous substrate. This study summarizes recent advances on green algal hydrogen metabolism and discusses avenues of research for the further development of this method. Included is the mechanism of a substantial tenfold starch accumulation in the cells, observed promptly upon S-deprivation, and the regulated starch and protein catabolism during the subsequent H2-evolution. Also discussed is the function of a chloroplast envelope-localized sulfate permease, and the photosynthesis-respiration relationship in green algae as potential tools by which to stabilize and enhance H2 metabolism. In addition to potential practical applications of H2, approaches discussed in this work are beginning to address the biochemistry of anaerobic H2 photoproduction, its genes, proteins, regulation, and communication with other metabolic pathways in microalgae. Photosynthetic H2 production by green algae may hold the promise of generating a renewable fuel from nature's most plentiful resources, sunlight and water. The process potentially concerns global warming and the question of energy supply and demand.

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Section: Temporal Separation Of O 2 -And H 2 -Evolutionmentioning

confidence: 98%