The Effect of Kanamycin and Tetracycline on Growth and Photosynthetic Activity of Two Chlorophyte Algae

Abstract

Antibiotics are routinely used in microalgae culture screening, stock culture maintenance, and genetic transformation. By studying the effect of antibiotics on microalgae growth, we can estimate the least value to inhibit growth of undesired pathogens in algal culture. We studied the effect of kanamycin and tetracycline on the growth and photosynthetic activity of two chlorophyte microalgae,Dictyosphaerium pulchellumandMicractinium pusillum.We measured CFU mL−1on agar plates, optical density, fluorescence yields, and photosynthetic inhibition. Our results showed a significant effect ofkanandteton the tested microalgae species excepttet,which showed a minor effect onM. pusillum.Both antibiotics are believed to interact with the protein synthesis machinery; hence, the inhibitory effect of the tested antibiotics was further confirmed by isolation and quantification of the whole cell protein. A significant reduction in protein quantity was observed at concentrations more than 5 mg L−1, exceptM. pusillum, which showed only a slight reduction in protein quantity even at the maximum tested concentration oftet(30 mg L−1). This study can further aid in aquaculture industry, for the maintenance of the microalgae stock cultures and it can also help the microalgae genetic engineers in the construction of molecular markers.