Symbiotic integration of microalgae (MA) with bacteria (methane oxidizing bacteria (MOB) and carbonic anhydrase-enriched bacteria (CAB)) for sustainable single-cell protein production from biogas

• Grant number: 24/14634-6
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: January 15, 2025
• End date: January 14, 2026
• Field of knowledge: Engineering - Sanitary Engineering - Water Supply and Wastewater Treatment
• Principal Investigator: José Alberto Domingues Rodrigues
• Grantee: Isabela Mehi Gaspari Augusto
• Supervisor: Irini Angelidaki
• Host Institution: Escola de Engenharia Mauá (EEM). Instituto Mauá de Tecnologia. São Caetano do Sul , SP, Brazil
• Institution abroad: Technical University of Denmark (DTU), Denmark
• Associated to the scholarship: 22/01425-4 - Two-stage hydrogen and methane production by the treatment of soybean processing waste (molasses and okara) in thermophilic and mesophilic condition, BP.DD

Abstract

Single-cell protein production is emerging as a potentially more sustainable alternative to plant-origin animal, due to the high protein content and its efficient production methods. Microalgae (MA) biomass production has gained attention as a platform for several bioproducts, such as such as carotenoids and vitamins production, raw materials for fuel (high lipids content), food formulation and health products, cosmetics, fertilizers, animal feed and bioplastics. feed. Another microorganism with the potential to generate protein-rich biomass is methane-oxidizing bacteria (MOB), which use methane as a sole carbon and energy source. One strategy to improve MA productivity is utilizing carbonic anhydrase enriched bacteria (CAB) that synergically interact with MA, converting carbon dioxide into dissolved inorganic carbon in order to avoid high outgassing rate of the CO2 and facilitate gas dissolution in liquid. In this context, the research project's objective is to evaluate the utilization of biogas (CH4 + CO2) as the substrate for a system composed of MA, CAB and MOB to produce single-cell proteins. Complementary, this study will establish a fundamental understanding of the mutualistic interactions and exchange of metabolites in the MOB-CAB-MA system, maximizing the growth of the three microbes. Under the optimized condition, specifically, depending on O2 availability in the system, the excretion of the dissolved organic compounds and intermediates will be maximized and lead to synergistic overall growth and enhanced protein production and amino acids content.