Microalga Growth-Promoting Bacteria as Strategy to Improve CO₂ Removal from Biogas

Developing microbial consortia emerges as a new research frontier since complementing metabolisms provides new biotechnological capabilities for symbiotic interaction. To date, microalgal consortia with other microorganisms, such as fungi, bacteria, or other microalga are considered a biotechnological strategy to enhance microalgal physiological performance during CO₂ removal from biogas—a gaseous by-product composed mainly of methane (CH₄, 65–70%) and CO₂ (25–30%) considered an energy source due to its high methane content. Today, microalga-microorganism interaction studies have focused on developing diverse microbial consortia to increase CO₂ fixation of biogas and their metabolic changes during processing time. Thus, the present review proposes in a novel way the use of microalgal growth-promoting bacteria (MGPB) as a suitable partner to boost microalgal physiological performance and positively influence CO₂ fixation from biogas. Furthermore, the MGPB mechanisms involved during MGPB-microalga interaction to mitigate or regulate microalgae metabolism under the stressful condition of this gaseous effluent and improve their biotechnological uses focusing on CO₂ removal from biogas are analyzed and proposed. Additionally, the microalgal ability to convert CO₂ from biogas into high-value biotechnological compounds of commercial interest is analyzed, including the economic feasibility and scalability of a microalga-MGPB consortium. This physiological knowledge of microalga-MGPG consortia notably warrants its real impact on different economic sectors as a bio-economy overview. Furthermore, the discussion between engineering and biological sciences facilitates the development of suitable bioprocesses based on microalgae.