الفهرس 
Culture techniquesOnly 14 pages are availabe for public view
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Abstract
This work aims to study the effect of different concentrations of phenolic compounds (cinnamic, phydroxybenzoic and salicylic acids) on the growth and some metabolic activities of two unicellular green algal species Chlorella vulgaris and Scenedesmus bijuga. The obtained results could be summarized as follows: 1) Growth of both tested organisms at low levels of cinnamic, p-hydroxybenzoic and salicylic acids stimulate the growth expressed as optical density and dry weight. However, high concentrations of the tested phenolic acids decline the growth of both organisms. On the other hand, the toxicity of phenolic acids at high concentrations under different growth conditions of both algae followed the order cinnamic acid > salicylic acid > p-hydroxybenzoic acid. 2) Data indicated that the different pigment fractions (chlorophyll a , chlorophyll b and carotenoids) were increased with low concentrations of the tested phenolic acids, whereas higher concentrations were accompanied by significant reduction in the pigment contents with great reduction in chlorophyll b. 3) The photosynthetic 02-evolution of both experimental algae were increased at low concentrations of the tested phenolic acids, while reduction was recorded at the higher concentrations. 4) The total soluble proteins of both organisms were significantly increased in cultures treated with low concentrations of the tested phenolic acids, whereas, the higher concentrations reduced protein biosynthesis. 5) The total amino acids of both experimental algae were affected by the tested phenolic acids levels.