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.