Photosynthetic characterization of a mutant of Spirulina platensis

摘要

A mutant of Spirulina (Arthrospira) platensis. strain 122, obtained by mutagenesis with ethylmethanesulfonate, was partially detective in the production of gamma-linolenic acid. However, when compared with the wild form, the 122 mutant almost lost its capacity to grow at low temperatures, although at optimal temperature growth was unaffected. Measurement of the mutant's photosynthetic characteristics, including O-2-evolution, Pmax and light saturation values, revealed significantly lower values than for the wild type, in contrast to the higher content of photosynthetic pigments. chlorophyll and phycocyanin. Whereas the total activity of photosynthesis of the 122 mutant was 58% lower than that of the wild type. the PS 11 activity of the 122 mutant was 23% higher. On the other hand, the 122 mutant was 69% lower in PS I activity, and the growth rate of this mutant was limited at high light intensity. These results indicated that the defect in the PS I complex of the 122 mutant may reduce its ability to utilize light to generate the energy used in diverse biochemical processes, including fatty acid desaturation. [References: 16]