Characterization of a Microalgal UV Mutant for CO(2) Biofixation and Biomass Production

The mutagenesis is an emerging strategy for screening microalgal candidates for CO(2) biofixation and biomass production. In this study, by 96-well microplates-UV mutagenesis, a mutant stemmed from Scenedesmus obliquus was screened and named as SDEC-1M. To characterize SDEC-1M, it was cultivated under air and high level CO(2) (15% v/v), and its parental strain (PS) was considered as control. Growth characterizations showed that SDEC-1M grew best in high level CO(2). It indicated that the mutant had high CO(2) tolerance (HCT) and growth potential under high level CO(2). Richer total carbohydrate content (37.26%) and lipid content (24.80%) demonstrated that, compared to its parental strain, SDEC-1M was apt to synthesize energy storage materials, especially under high CO(2) level. Meanwhile, the highest light conversion efficiency (approximately 18 %) was also obtained. Thus, the highest overall biomass productivities were achieved in SDEC-1M under high level CO(2), largely attributed to that the highest productivities of total lipid, total carbohydrate, and crude protein were also achieved in the meantime. By modified UV, therefore, mutagenized SDEC-1M was the better candidate for CO(2) biofixation and biofuel production than its parental strain.