Production of amino acids by analog-resistant mutants of the cyanobacterium Spirulina platensis

Abstract
Mutants of S. platensis resistant to 5-fluorotryptophan, .beta.-2-thienylalanine, ethionine, p-fluorophenylalanine or azetidine-2-carboxylic acid were isolated. Some of these mutants appeared to be resistant to more than 1 analog and to overproduce the corresponding amino acids. A 2nd group was composed of mutants that were resistant to 1 analog only. Of the latter mutants, one resistant to azetidine-2-carboxylic acid overproduced proline only; one resistant to fluorotryptophan and one resistant to ethionine did not overproduce any of the tested amino acids.