Effect of isomers of hydroxybenzoic acid on the growth and metabolism of Chlorella vulgaris beijerinck (chlorophyceae)

The isomers o-, m-, and p- of hydroxybenzoic acid (HBA) in the concentration range 10(-6)-10(-4) M in the unicellular green alga Chlorella vulgaris (Chlorophyceae) display marked biological activity. The o-HBA isomer, commonly known as salicylic acid, in a concentration of 10(-4) M exerted the most stimulating effect on the parameters analysed (the number of cells, dry mass, the content of chlorophylls a and b, carotenoids, soluble proteins and their secretion, monosaccharides, DNA and RNA) whereas p-HBA had weak stimulating properties. On the other hand, m-HBA had a weak inhibitory effect on the growth of C. vulgaris and all the biochemical parameters analysed in comparison with the control culture of algae devoid of HBA isomers.