I am a PhD Student from the Faculty of Sciences of the University of Lisbon working at Laboratório Nacional de Energia e Geologia (LNEG, National Laboratory for Energy and Geology) in the Bioenergy Unit. My work is part of the R&D project GreenFuel (website: http://www.lneg.pt/iedt/projectos/620/), and is centred on biodesulfurization, a process that makes use of microorganisms to remove sulphur from fuels. Unlike the chemical alternatives, biodesulfurization can occur at environmental conditions, being especially efficient with complex organosulfur molecules. It was initially studied to be used in fossil fuels; however, it can also be used for alternative fuels, such as pyrolysis oils, which can have high concentrations of sulphur. For biodesulfurization to be economically feasible, it will depend on the valorisation of high-added value by-products, produced by its biocatalysts.
My work is centred on a desulfurizing bacterium Gordonia alkanivorans strain 1B, which is known to produce carotenoids and biosurfactants, two high value products, with interesting properties for many industries. Depending on growth conditions, this bacterium will present different colorations, and surfactant activities. To correctly assess the value of these substances and determine their influence on process efficiency, it becomes fundamental to identify/characterize them, which has been impossible for most of the carotenoids or surfactants using the methods available to me.
My PhD supervisors, from LNEG, advised me to apply to a Brisk II call since it could help me access equipment and knowledge that was unavailable in our lab. So, after analysing the facilities and equipments shared by the different partners, I decided to contact the High Throughput Mass Spectrometry Unit at SINTEF, Trondheim.
The trip to SINTEF occurred in the first two weeks of September 2019 and my work was performed under the supervision of Anders Brunsvik. On the first day, after a tour of their facilities, we had a meeting where he explained in detail the procedures and techniques we were going to use and gave me some bibliography and presentations that greatly helped me to understand the work we were going to perform, and how to interpret the results.
I brought to SINTEF thirteen carotenoid samples that were analysed through LC-MS Q-TOF and FT-ICR, with both positive and negative ionization. In the LC-MS Q-TOF, the best results were obtained under positive ionization. It was possible to identify seven different main peaks in the UV detector, corresponding to seven different compounds in the MS. Depending on the extract analysed, there were different combinations of these peaks.
The FT-ICR revealed different mass profiles for each extract, reinforcing that the different growth conditions greatly influence the compounds produced. This analysis revealed, as expected, the presence of several compounds, other than carotenoids, and generated a great amount of data (several thousand different masses were identified per sample), however, with the help of the analytical software it was possible attribute a theoretical formula to each mass. These results present a higher resolution and will help with the correct identification of the peaks detected in the LC-MS Q-TOF.
The biosurfactants have previously been especially hard to analyse, since they tend to precipitate easily. So, the FT-ICR at SINTEF was especially convenient, due to its capability to analyse solid samples. After testing several concentrations, three compounds were differentiated in the most concentrated surfactant sample. Of these, one presented added interest since its profile resembled that of a polymer.
This visit allowed me to acquire important data on the carotenoids and surfactants produced by Gordonia alkanivorans strain 1B and could also reveal the presence of other important metabolites, bringing value to the biodesulfurization process. This Brisk II application gave me the opportunity to access state of the art technology, which would otherwise be inaccessible, and allowed me to gain theoretical and practical experience with very specialized techniques, which very few places could offer, enriching my knowledge and increasing my set of skills. I would like to thank Anders, who, not only helped me through every step of the work, but also gave me great advices and answered all my of my questions about Norway and Trondheim, and Bernd and everyone at SINTEF Industry, for making these two weeks such a great experience.