ABSTRACT
Microalgae are remarkable communities in relation to their wide range adaptations to different adverse stress conditions. Physical stresses such as light intensity, temperature and turbulence affect the photosynthetic activities, leading to an inefficient carbon fixation; resulting in the overall growth of microalgae. The light intensity and temperature usually supports the linear growth up to the optimum level, while beyond that level they temporarily suspend with the normal growth processes, but facing a long time, microalgae invokes the photorespiration and photo inhibition respectively.
Small-scale turbulence has no such negative effect, usually helping in seasonal excessive growth i.e., algal blooms that are responsible for large scale nutrient cycling in major oceans to sustain marine life. In response to the nutrient limitation or starvation, microalgae tend to accumulate certain compounds such as lipids, carotenoids, polysaccharides and amino acids to survive the stress. Further they start to unlock the reserved nutrients like nitrogen from cycophycin granules and phosphorous from polyphosphate granules.
These successful strategies against stresses could help the microalgae to survive in various wastewaters. Microalgae mediated remediation could provide the efficient nutrient sequestration, improving the BOD, COD, color, odor and pathogenic microbes.
