My research was centred on syngas fermentation using autotrophic acetogenic bacteria, under the scope of the Ambition project at Laboratório Nacional de Energia e Geologia (LNEG, National Laboratory for Energy and Geology). Syngas is defined as the product of gasification, a high-temperature conversion process of a solid substrate into a gaseous product, and is mainly composed of carbon monoxide, carbon dioxide, hydrogen and methane. Syngas can be converted into either energy, directly by combustion, or into high added value compounds, by bacteria that use the gas as carbon source. Even though this process has an integrated processing stage for minimization of inhibitory compounds (cleaning stage by condensation), the obtained syngas can still contain high amounts of compounds which hinder the fermentation process.
To test the effect of such inhibitors on syngas fermenting bacteria, eight lignin syngas condensates were collected. The tested condensates were obtained during gasification using different lignins, gasification temperatures and catalysers at the gasification facility of LNEG. When added to the culture medium in similar fermentation conditions, different condensates influenced the bacterial cultures in distinctly different manners.
Since my home institution did not have the resources for the identification of the different compounds present in the condensates, I applied to Brisk II transnational access in order to access the High Throughput Mass Spectrometry Unit at SINTEF, Trondheim.
The visit to SINTEF was performed in the two first weeks of September 2019, under the supervision of Anders Brunsvik. The eight condensates were analysed through two mass spectrometers at SINTEF: an LC-MS Q-TOF and a GC-MS, both in positive and negative ionization modes. The analysis of the chromatograms was performed using the Agilent qualitative analysis software and the resulting masses and spectra were compared with several databases in order to be identified.
The results obtained showed significant differences between the analysed condensates. A total of 63 different compounds were identified. The condensates with a higher variety of identified compounds reached a maximum of 38 hits, while the condensate with the least identified compounds had only 7 hits. Many of the components found in these condensates are known cellular growth inhibitors, and their presence and/or absence can be indicative of the obtained results during the growth assays.
The data acquired during this visit will allow a better comprehension of the effect of crude syngas in the fermentation process, enriching a research area in which there is very little knowledge. Brisk II allowed me to have a “hands-on” experience in the operation of high-tech equipment and associated techniques that would be otherwise inaccessible to me, enriching my scientific curriculum. I wanted to thank Anders for his patience and for kindly answering to all my doubts and to Bernd and all the team at SINTEF Industri for their warm welcome and for making me feel at home.