Extracellular Enzyme Activity and Growth of Chlorella sorokiniana in Response to CO2, Light Color, and Light Intensity in a Photobioreactor.

Microalgae are valuable sources of biotechnological products for industrial applications. The increasing interest in microalgal biomass has also highlighted its ability to release extracellular byproducts, including enzymes of industrial relevance, into the culture medium. This study evaluated the combined effects of CO2 availability, nitrogen levels, light color, and light intensity on the growth and extracellular amylolytic and lipase activities of Chlorella sorokiniana using a Taguchi L4 experimental design. Cell growth and lipase activity were favored under purple light and moderate light intensity at low CO2 supplementation, whereas amylolytic activity was enhanced under purple light combined with increased CO2 availability and lower light intensity. Overall, light color emerged as the main factor influencing both growth and extracellular enzyme production, followed by CO2 concentration and light intensity. These findings demonstrate the potential of controlling light and carbon supplies to modulate microalgal growth and extracellular enzyme activity, supporting the development of integrated and sustainable microalgal bioprocesses.