New discovery increases bioethanol production efficiency and profits

A new technique to track contamination in bioethanol production could increase revenue by more than $1.6 billion and reduce CO₂ emissions by 2 million tons.

For the first time ever, researchers from The Novo Nordisk Foundation Center for Biosustainability (DTU Biosustain) investigated a population of contaminants from the sugarcane bioethanol production process at a strain-level resolution. Their study reveals how deformation dynamics are directly involved in process performance and highlights the need for improved microbial control techniques to increase industrial efficiency. The research results appear in The nature of communication.

Higher process yield and environmental benefits

Bioethanol, a major renewable energy source, comes from the fermentation of sugars by yeast, primarily Saccharomyces cerevisiae. However, contaminating bacteria present in the raw material can significantly affect the efficiency of fermentation. Until now, these contaminating microbes have been characterized using methods that do not fully capture their diversity or impact.

“Our research provides a comprehensive analysis of microbial populations in all stages of the industrial bioethanol process in two large Brazilian biorefineries. Using a combination of shotgun metagenomics and cultivation-based methods, we identified ecological factors that influence community dynamics and bioconversion efficiency,” he added. says postdoc Felipe Lino from DTU Biosustain. “The study shows that specific bacterial strains, affected by temperature, can either hinder or increase ethanol yield. This improvement can only be achieved with the advanced techniques we used.”

The findings could lead to more than a 5% increase in process yield, translating into approximately $1.6 billion in increased revenue and CO reduction₂ emissions by around 2 million tons per year if we consider Brazil alone.

Strain-level resolution: Unraveling hidden bacterial dynamics

The researchers found that the interplay between different species significantly affects ethanol yield. Whenever Lactobacillus amylovorus is present in higher concentrations, yields are significantly better.

Professor Morten Sommer from DTU Biosustain explains: “We mapped microbial populations at a strain-level resolution to reveal the true impact of non-yeast microbes on fermentation performance. We identified specific strains of the L. fermentum species that cause the most damage to the process, while other strains are neutral and they should even be maintained as a buffer against harmful ones.

“Increased temperatures were associated with the growth of specific strains of L. fermentum that negatively affect yeast viability and fermentation efficiency. This underscores the importance of adopting higher resolution methods in the future to monitor microbial communities.”

It paves the way for new microbial and process solutions

The results of this study could lead to the development of new microbial and process control solutions that can control unwanted microbes and unlock significant performance improvements in bioethanol production. This can translate into more cost-effective biofuels, higher efficiency and substantial CO reduction₂ emissions, which supports global efforts to reduce greenhouse gas emissions.

The research results are particularly relevant for biofuels and industrial biotechnology companies, as well as research groups focused on bioinformatics tools for microbiome analysis with strain-level resolution. The new gene catalog and functional analyzes developed in this study offer valuable resources for discovering new enzymes and metabolic properties for robust industrial strains. These findings could also be applied to other metagenomic studies such as gut microbiome dynamics, soil and crop-related microbiomes.