Response of energy microalgae Chlamydomonas reinhardtii to nitrogen and phosphorus stress

摘要

AbstractMicroalgae can effectively absorb nitrogen (N) and phosphorus (P) in wastewater, while growth characteristics can be affected by such nutrients. The influences of the N and P concentration on growth, biomass yield, protein yield, and cell ultrastructure ofChlamydomonas reinhardtii(C. reinhardtii) were investigated in this study. The results showed that, in the optimum conditions (24–72?mg/L for N and 4.5–13.5?mg/L for P), the final biomass and protein content ofC. reinhardtiicould reach maximum value, and the cell organelles (chloroplast, mitochondria,etc.) showed good structures with larger chloroplasts, and more and neater thylakoids. However, if the concentration of nutrients was much higher or lower than the optimal value, it would cause adverse effects on the growth ofC. reinhardtii, especially in high nitrogen (1000?mg/L) and low phosphorus (0.5?mg/L) conditions. Under these extreme conditions, the ultrastructure of the cells was also damaged significantly as follows: the majority of the organelles were deformed, the chloroplast membrane became shrunken, and the mitochondria became swollen, even partial disintegrated (differing slightly under high-N and low-P conditions); furthermore, it is found thatC. reinhardtiiwas more sensitive to low-P stress. On the basis of these results, our findings have general implications in the application of wastewater treatment.]]>