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Lipid accumulation and biodiesel quality of Chlorella pyrenoidosa under oxidative stress induced by nutrient regimes

Zhang, Lei, Wang, Nan, Yang, Mei, Ding, Ke, Wang, Yong-Zhong, Huo, Danqun, Hou, Changjun
Renewable energy 2019 v.143 pp. 1782-1790
Chlorella pyrenoidosa, biodiesel, cell growth, energy conversion, fatty acid composition, fuel production, lipid content, lipids, nitrogen, oxidative stress, phosphorus, principal component analysis, reactive oxygen species, sulfur
In this study, effects of media compositions on the suitability of Chlorella pyrenoidosa lipids for biodiesel production were investigated. The results indicate that sulfur deficiency and excessive phosphorus resulted in significant inhibition of cell growth. Moreover, the cellular lipid content increased under nitrogen-, phosphorus- or sulfur-deficient conditions, with the maximal lipid content of 48.90% and energy conversion efficiency of 8.89% being reached under nitrogen deficient conditions. In all runs, C16 to C18 components accounted for more than 95% of the total fatty acids. In addition, several biodiesel quality parameters were calculated according to the fatty acid profile, and principal component analysis and cluster dendrogram analysis were used to evaluate the quality of the corresponding biodiesel. A high similarity of biodiesel quality under nitrogen-, phosphorus- or sulfur-deficient cultivation was observed, and the biodiesel quality was better than those obtained under other culture conditions. Additionally, a strong correlation between lipid accumulation and reactive oxygen species level was confirmed. Overall, the work indicates that the lipid content of C. pyrenoidosa increased under nitrogen-, phosphorus- or sulfur-deficient conditions and the biodiesel quality was also improved.