BIOLOGY OF MICROALGAE AND PHOTOBIOREACTOR-BASED CULTIVATION: A REVIEW

Abstract

Microalgae are microscopic photosynthetic organisms with significant ecological and biotechnological potential. They convert light energy and carbon dioxide into biomass rich in proteins, lipids, carbohydrates, pigments, vitamins, minerals, and other bioactive compounds. Photobioreactors provide controlled cultivation environments where light, temperature, pH, nutrients, carbon dioxide supply, mixing, and gas-liquid mass transfer can be optimized. This review analyzes the biological basis of microalgae cultivation and evaluates major photobioreactor configurations, including open raceway ponds, tubular systems, flat-panel photobioreactors, bubble-column reactors, airlift reactors, and stirred-tank photobioreactors. The findings show that closed photobioreactors offer superior process control and lower contamination risk, while open systems remain economically attractive for large-scale low-cost biomass production. Hybrid systems may provide a balanced strategy by separating biomass growth from product induction phases.