How Different Fats Can Boost Methane Production

Anaerobic digestion (AD) is a method where microorganisms convert organic materials, like food scraps and sludge, into biogas, which can be used as a renewable energy source. The efficiency of AD can be influenced by different types of fatty acids. Fatty acids are found in many products and biological processes. However, the impact of different types of these acids on anaerobic digestion has not been fully understood. One type, called cis oleic acid (COA), is commonly found in many foods. A study showed that a specific type of fatty acid, called trans-oleic acid (TOA), increased methane production by 56% during the digestion of food waste and sludge. In comparison, the same amount of cis-oleic acid (COA) led to only a 20% increase in methane production. Researchers delved deeper using techniques, such as genome-centric meta-omics, to understand the role of microorganisms. They had a particular interest in how different fatty acids affect a process called acidogenesis. The study found that four types of microorganisms—three acidogenic and one hydrogenotrophic methanogen—were present in both TOA- and COA-enhanced AD. The increased production of methane can be explained by these species, which contribute significantly to stronger acidification and hydrogenotrophic methanogenesis. The study also found that the TOA type enhanced production with two additional didermal acidogens. The key take-away is that different fatty acids can alter how microbes process organic waste and result in different levels of methane production. This research highlights the potential to manipulate the digestion process by using specific fatty acids, which could lead to more efficient energy conservation and help reduce carbon emissions. Understanding the conversion process can lead to better waste management and more sustainable energy sources.