Chinese researchers study microbes to help lower toxicity in lignocellulosic microbial fermentation

In China, as the global push for sustainable biofuels intensifies, lignocellulosic biomass has emerged as a prime candidate for biofuels and biochemicals owing to its abundance and renewability. This biomass, derived from plant materials, holds great promise as a feedstock for biofuel production. However, the pretreatment process required to break down lignocellulose often yields toxic byproducts like lignin-derived phenolic compounds and furanyl aldehydes. These byproducts can severely inhibit microbial fermentation, a critical step in biofuel production, thereby reducing overall efficiency. Effective detoxification of these byproducts is essential for optimizing the conversion process and making lignocellulosic biomass a viable alternative to fossil fuels.

To tackle the challenge of byproduct toxicity, researchers from Nanjing Tech University, China, carried out a study focusing on the potential of two microbial strains—Rhodococcus aetherivorans strain N1 and its genetically modified variant, strain N1-S. The study was published in BioDesign Research on 15 August 2024 and investigates the ability of these strains to detoxify the harmful compounds present in lignocellulose derivatives and their subsequent impact on the production of succinic acid, a valuable biofuel precursor. By assessing their detoxification capability, the study aims to address the current limitations of detoxification methods and improve biofuel production efficiency.

The study employed a multifaceted approach involving laboratory experiments to test the degradation capabilities of strains N1 and N1-S. Strain N1 is being analyzed for its ability to degrade a range of toxic compounds under controlled conditions. The metabolic pathways involved in these degradation processes are being mapped to understand how these microorganisms handle different byproducts. Furthermore, strain N1-S, a genetically engineered strain to specifically enhance the degradation of syringaldehyde—a challenging compound poorly processed by the naturally occurring strain N1—is being evaluated. Both strains are being tested using corn cob derivatives obtained from dilute acid pretreatment, simulating a real-world lignocellulosic biomass processing scenario.