The effect of reducing light-harvesting pigment on marine microalgal productivity

The productivity was evaluated of a strain of Chlamydomonas perigranulata isolated from the Red Sea. A mutant with small light-harvesting pigments (LHC-1) was obtained by UV mutagenesis. The chlorophylls content of the wild type was twice as high as that of LHC-1, and the initial slope of the photosynthesis-irradiance curve was higher in the wild type. However, the maximum photosynthetic activity on a per cell basis was almost the same. It is concluded that LHC-1 is a mutant with less light-harvesting pigment (LHP) than the wild type. As previously reported, the mutant with lower LHP content has a higher productivity in a continuous culture system, so we compared the productivity of the wild type and the mutant. The maximum productivity of LHC-1 was 1.5 times higher than that of the wild type. It is suggested that the technique of reducing the content of light-harvesting pigment should be made available for other organisms.