Abstract: This study presents a comprehensive analytical review of current technologies for carbon dioxide (CO₂) fixation and utilization, with a particular focus on the application of microalgae as a biological tool for mitigating industrial emissions and contributing to hydrogen energy systems. The aim is to identify optimal cultivation parameters that enhance CO₂ absorption efficiency and to evaluate the feasibility of integrating microalgal systems into energy and industrial sectors of the Russian Federation, with emphasis on their role in biohydrogen production and carbon-neutral hydrogen pathways.

The research is based on a systematic literature review using databases such as PubMed, Scopus, Web of Science, and eLIBRARY. Keywords included “carbon dioxide,” “microalgae,” “biohydrogen,” “photosynthesis,” “circular economy,” “CO₂-concentrating mechanism,” “hydrogen production,” and “algal bioreactors.” Theoretical methods such as deconstruction, axiomatization, diachronic analysis, and descriptive modeling were employed to synthesize findings. Physiological and ecological parameters—photoperiod, light intensity, temperature, pH, CO₂ concentration, and nutrient composition—were analyzed to determine their influence on photosynthetic carbon fixation and hydrogen-generating metabolic pathways.

Microalgae demonstrate high potential for CO₂ capture due to their rapid biomass growth, high photosynthetic efficiency, and adaptability to diverse environments. The optimal conditions for CO₂ fixation were identified as follows: photoperiod of 16–18 hours light and 6–8 hours darkness; light intensity of 100 μmol/m²/s or approximately 5405 lux; temperature range of 20–25°C; pH between 6.0 and 8.3; CO₂ concentration up to 5%; and nutrient supplementation with 0.02% urea and 0.05% sodium bicarbonate.

These parameters significantly enhance enzymatic activity, particularly of Rubisco, and support the CO₂-concentrating mechanism (CCM) in microalgae. Species such as Chlorella vulgaris, Nannochloropsis sp., and Scenedesmus were found to be particularly effective under these conditions. In addition to CO₂ fixation, these species exhibit promising traits for biohydrogen production through photobiological and fermentative pathways.

Shinkevich, P.S., Velmozhina, K.A., Politaeva, N.A. and Chusov, A.N., 2025. The role of microalgae in modern technologies for carbon dioxide fixation and utilization. International Journal of Hydrogen Energy, p.153074. https://10.1016/j.ijhydene.2025.153074