Nitrogen ion beam implantation for enhanced lipid accumulation of Scenedesmus obliquus in municipal wastewater

Abstract Breeding of high-lipid content microalgae in municipal wastewater is critical for large-scale microalgal biodiesel production. In this study, a strain of biodiesel promising microalga Scenedesmus obliquus with good stain resistance was obtained by N+ ion implantation, which was named as S1-A3. In the selenite enrichment (SE) medium, the lipid content of S1-A3 was up to 46.92%, which was increased by 24.1% than the original strain. Meanwhile, after 7 days of cultivation, the removal rates of TP,TN, NH4+-N and COD in wastewater attained 95.72%, 80.30%, 87.25% and 85.43% by S1-A3, respectively. S1-A3 had a good genetic stability in both municipal wastewater and SE medium, and its lipid production capacity was improved after four successive cultivation in wastewater. RAPD analysis showed that the mutant and the original strain were interspecific variations. Therefore, N+ ion implantation was proved to be an approach that can significantly improve the lipid content and adaptability of Scenedesmus obliquus.