Hydrogen photoproduction in green algae Chlamydomonas reinhardtii under magnesium deprivation

Abstract

Mg deprivation results in the sustained H2 formation in Chlamydomonas reinhardtii.

Multiple regulatory mechanisms in the chloroplast of green algae: relation to hydrogen production

“…Although S-deprivation is considered as a basic method to sustain hydrogen photoproduction in green algae, recently many attempts have been made to test depletions on other important nutrients, including nitrogen, phosphorus, magnesium, and potassium (Philipps et al 2011;Batyrova et al 2012Batyrova et al , 2015He et al 2012;Papazi et al 2014;Volgusheva et al 2015). As shown by Philipps et al (2011), metabolic modifications observed upon nitrogen limitation in C. reinhardtii qualitatively resemble those evoked by sulfur deficit, although each type of depletion induces nutrient-specific physiological responses.…”

“…For example, marine Chlorella species evolve similar amounts of hydrogen as phosphorus-deprived C. reinhardtii when cultivated in sea or salt water supplied with acetate and some other components of the standard tris-acetate-phosphate medium. Unlike depletions of phosphorus or nitrogen which are less effective stimuli for hydrogen photoproduction in C. reinhardtii than sulfur deficiency, magnesium deprivation seems to be more effective (Volgusheva et al 2015). Since Mg 2?…”

Relevance of nutrient media composition for hydrogen production in Chlamydomonas

“…These two factors seem to occur much faster under Mg and S deficiency than under P or N deficiency Philipps et al 2012;Volgusheva et al 2014). In the case of P depletion, this could be partially attributed to the internal reserves of P that delay a severe P-stressed situation and help cell survival.…”

“…For example, H 2 production in Mg-and S-depleted cultures occurs mainly via the PSIIdependent pathway Volgusheva et al 2014), whereas in N-depleted cultures, it could occurs essentially via the fermentation Philipps et al 2012). Still, for S and Mg deficiency, about 20-30 % of H 2 production is linked to the PSII-independent pathway.…”

“…Finally, prolonged nutrient stress can cause the mobilization of internal reserves as sources of ATP with the concomitant generation of reduced equivalents (predominantly NADH and NAD(P)H). Indeed, the mobilization phase of internal metabolites (e.g., starch and proteins) is often reported to be coordinated with the H 2 -production phase Aparicio et al 1985;Batyrova et al 2012;Volgusheva et al 2014). …”