Evaluation of UV-Induced Mutants of Chlorella vulgaris for Single Cell Protein I. The Screening Effect of Cycloheximide and 6-Methylpurine

Chlorella vulgaris was irradiated with UV doses allowing a 0.1 per cent survival. Dark recovery and photoreactivation were carried out either in the presence or in the absence of an inhibitor of protein synthesis. Faster growing and faster greening colonies were selected, and the amino acid composition of the mutant strains were evaluated. Higher growth and photosynthetic rates, higher chlorophyll content and lower respiration rate were shown by all mutants irrespective of the selection procedure. Selection against cycloheximide led to higher protein and RNA, but lower carotenoid content, whereas mutants selected against 6-methylpurine showed, in addition to a protein and carotenoid increase, a more favourable protein: RNA ratio.