Accelerating Bio-Aviation Fuel Research with Raman Spectroscopy

Recently, a team of researchers from Beijing University of Chemical Technology conducted a study that highlighted how in-situ Raman spectroscopy can help accelerate the development of bio-aviation fuels. This study, which was led by researcher Meng Wang of Beijing University of Chemical Technology and published in the journal Sustainable Energy Technologies and Assessments, demonstrated that online Raman analysis can detect β-farnesene, which is a key biofuel precursor, up to 48 times faster than conventional technologies (1).

Bio-aviation fuels are rapidly advancing because of a global push around reducing carbon emissions. Sustainable aviation fuel (SAF) is part of this push. SAF takes renewable biomass and waste resources to use as a fuel alternative for petroleum-based jet fuels (2). Scientists have been able to achieve the performance of petroleum-based jet fuels while reducing carbon emissions (2).

The past 15 years have seen even further advancements. In 2021, the American Society for Testing and Materials (ASTM) gave approval of the hydro-processed esters and fatty acids (HEFA) pathway in 2011 and the direct sugar to hydrocarbon (DSHC) pathway in 2014 (1). Both processes relied on efficient microbial fermentation to produce chemical intermediates such as terpenes and fatty acids (1). Despite all of this progress in fuel chemistry, the real-time monitoring of fermentation remains a major bottleneck, limiting researchers’ ability to optimize production at scale.

For the real-time monitoring of fermentation, techniques such as gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS) have been used. Although GC and GC–MS provide the accuracy, they are poorly suited for rapid screening or continuous monitoring (1). That is because these methods require intensive sample preparation, are destructive to the sample, and take 20–35 minutes for each measurement (1). In fast-moving fermentation systems, where conditions can shift quickly, these delays impede process control and slow down strain screening efforts.

In their study, Wang and colleagues developed the first quantitative online Raman spectroscopy method for β-farnesene detection during fermentation. Their approach was designed to shorten the testing time from 20 minutes to just 25 seconds, removing the need for pretreatment steps (1). The ability of Raman spectroscopy to capture molecular information from aqueous samples without altering them makes it an ideal candidate for real-time bioprocess monitoring.

β-Farnesene, a well-studied sesquiterpene and an important precursor in renewable jet fuel production, served as the model compound for the study. The team evaluated how Raman spectroscopy could rapidly quantify β-farnesene levels directly from fermentation wells, enabling high-throughput strain screening (1). The experimentation included optimizing measurement distance and other key detection parameters to ensure accuracy and reproducibility (1).

A major advantage of the new system was its compatibility with 24-well fermentation plates, a standard platform for microbial screening. Instead of extracting samples and transporting them to an analytical lab, researchers can now perform direct, in-situ Raman measurements on each well. The method showed relative errors within 5% for single-phase extractant systems and within 10% when applied directly to post-fermentation wells, which are levels of precision that are considered highly reliable for rapid screening purposes (1).

What are the main takeaways from this study?

This Raman-based method enabled swift, non-destructive detection for high-throughput screening of strains producing terpenes, fatty acids, and other bio-aviation fuel precursors. This means that this technique could potentially applied to other biofuel research programs, not just aviation fuel (1). Because of the method’s success characterizing β-farnesene, the study also suggests that the in-situ Raman spectroscopy method could be applied to other compounds with chemical characteristics to β-farnesene (1).

This study paves the way for more research into sustainable aviation. Carbon-neutral fuels are becoming more pervasive because of global demand, and as a result of this trend, having a method that could evaluate microbial strains and fermentation conditions more quickly could help shorten development timelines and scale production technologies more efficiently (1). The study positions Raman spectroscopy as not merely a supplementary technique, but a central tool for future bioprocess innovation (1).

References

1. Dong, H.; Zhang, H.; Wang, M.; et al. Rapid Analysis of Sustainable Aviation Fuel Precursor in a Fermentation System based on In-situ Raman Spectroscopy. SETA 2025, 76, 104305. DOI: 10.1016/j.seta.2025.104305
2. U.S. Department of Energy, Sustainable Aviation Fuels. Energy.gov. Available at: https://www.energy.gov/eere/bioenergy/sustainable-aviation-fuels (accessed 2025-12-08).