Biochemical composition of Microcystis aeruginosa related to specific growth rate: insight into the effects of abiotic factors

The content of different Microcystis biochemical components, including total polysaccharides (TPS), proteins, and RNA, were analyzed at different growth rates obtained under varying light intensities, temperatures, and nutrient concentrations. Higher light intensity and temperature yielded a higher specific growth rate of Microcystis, but the 2 different culture media did not significantly affect growth of Microcystis in the current study. The differences in the cellular content of TPS, protein, and RNA at different temperatures (20 and 25 degrees C) were significant under both light intensities. The differences under different light intensities (30 and 60 mu mol photons m(-2) s(-1)) were significant at 25 degrees C but negligible at 20 degrees C. These phenomena suggested that temperature would be the limiting factor influencing the cellular processes when temperature was 20 degrees C; however, when temperature was 25 degrees C, the limiting factor was observed to be light intensity. The results also demonstrated that the content of TPS and RNA decreased, but the value of proteins increased with an increase in specific growth rate.