Catalytic fast pyrolysis of biomass over microporous and hierarchical zeolites: characterization of heavy products

The conversion of lignocellulosic biomass by catalytic fast pyrolysis (CFP) is a promising route to producing green aromatics and sustainable biofuels. The zeolite catalysts present a strong ability to produce light aromatics but also heavy products. In this work, these heavy products are monitored by a well-established petroleomic approach. The selectivity toward the heavy bio-oil components of both a common HZSM-5 zeolite and a hierarchical zeolite was investigated. Part of the molecular species from lignin derivatives is still present in the upgraded bio-oils. Deoxygenation and aromatization are the main modifications of the heavy compounds caused by zeolites, especially for the sugar derivatives. These effects are stronger for the hierarchical zeolite for which numerous heavy hydrocarbons (not oxygenated) are generated due to enhanced mass transfers within the crystallites. Moreover, this catalyst demonstrates a better stability upon an increase in the biomass-to-catalyst ratio

Combination of electrospray ionization, atmospheric pressure photoionization and laser desorption ionization Fourier transform ion cyclotronic resonance mass spectrometry for the investigation of complex mixtures - Application to the petroleomic analysis of bio-oils

The comprehensive description of complex mixtures such as bio-oils is required to understand and improve the different processes involved during biological, environmental or industrial operation. In this context, we have to consider how different ionization sources can improve a non-targeted approach. Thus, the Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) has been coupled to electrospray ionization (ESI), laser desorption ionization (LDI) and atmospheric pressure photoionization (APPI) to characterize an oak pyrolysis bio-oil. Close to 90% of the all 4500 compound formulae has been attributed to CHO with similar oxygen class compound distribution. Nevertheless, their relative abundance in respect with their double bound equivalent (DBE) value has evidenced significant differences depending on the ion source used. ESI has allowed compounds with low DBE but more oxygen atoms to be ionized. APPI has demonstrated the efficient ionization of less polar compounds (high DBE values and less oxygen atoms). The LDI behavior of bio-oils has been considered intermediate in terms of DBE and oxygen amounts but it has also been demonstrated that a significant part of the features are specifically detected by this ionization method. Thus, the complementarity of three different ionization sources has been successfully demonstrated for the exhaustive characterization by petroleomic approach of a complex mixture

Untargeted Metabolomics Reveals Antidepressant Effects in a Marine Photosynthetic Organism: The Diatom Phaeodactylum tricornutum as a Case Study

The increased use of antidepressants, along with their increased occurrence in aquatic environments, is of concern for marine organisms. Although these pharmaceutical compounds have been shown to negatively affect marine diatoms, their mode of action in these non-target, single-cell phototrophic organisms is yet unknown. Using a Fourier-transform ion cyclotron-resonance mass spectrometer (FT-ICR-MS) we evaluated the effects of fluoxetine in the metabolomics of the model diatom Phaeodactylum tricornutum, as well as the potential use of the identified metabolites as exposure biomarkers. Diatom growth was severely impaired after fluoxetine exposure, particularly in the highest dose tested, along with a down-regulation of photosynthetic and carbohydrate metabolisms. Notably, several mechanisms that are normally down-regulated by fluoxetine in mammal organisms were also down-regulated in diatoms (e.g., glycerolipid metabolism, phosphatidylinositol signalling pathway, vitamin metabolism, terpenoid backbone biosynthesis and serotonin remobilization metabolism). Additionally, the present work also identified a set of potential biomarkers of fluoxetine exposure that were up-regulated with increasing fluoxetine exposure concentration and are of high metabolic significance following the disclosed mode of action, reinforcing the use of metabolomics approaches in ecotoxicology.info:eu-repo/semantics/publishedVersio

Étude par spectrométrie de masse à haute résolution de bio-huiles issues de la pyrolyse de la biomasse lignocellulosique

The products of lignocellulosic biomass pyrolysis are potential sources of renewable materials such as bio-fuels, biochars, and chemicals. However, their ready-to-use capacity is limited by their high chemical complexity and their high oxygen content. Therefore, they have to be upgraded by different treatments such as deoxygenation and/or cracking. In order to assess the most suited upgrading process, it is necessary to obtain an extensive composition description of the raw pyrolysis products. The works carried out during this PhD thesis are dealing with the development of though analytical methods to reach the most detailed composition description of bio-oils. This study was performed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) using different ionization sources. The electrospray ionization (ESI), in controlled-conditions, ensures to ionize the cellulose and the hemicellulose derived compounds as well as the lipids and the lignin derivatives. The atmospheric pressure photoionisation (APPI) and the laser desorption/ionization (LDI) allow specifically to detect more unsaturated pyrolytic lignin species. The combination of the different results ensures to obtain an extensive bio-oil description. The established methodology was applied to raw and upgraded (catalytic deoxygenation/cracking treatment on different zeolites) bio-oils. The ESI FT-ICR MS measurements evidenced the selectivity of the used catalysts on sugaric compounds whereas the APPI and LDI highlighted the nature of the resulting compounds which are less oxygenated and produced, for a part of them, by catalytic crackingLes produits de la pyrolyse de la biomasse lignocellulosique présentent un potentiel important dans le cadre des ressources renouvelables. Cependant, leur utilisation directe est réduite en raison de leur importante complexité et de leur teneur élevée en oxygène. Il est nécessaire de leur faire subir des traitements de désoxygénation et/ou de craquage. Afin de déterminer quels sont les traitements les mieux adaptés, il est indispensable de connaitre aussi précisément que possible leur composition. Les travaux menés dans le cadre de cette thèse portent sur la mise en place de méthodologies d’analyse robustes pour obtenir la description la plus exhaustive possible des bio-huiles. Pour cela, la spectrométrie de masse à résonance cyclotronique d’ions à transformée de Fourier (FT-ICR MS) a été employée en couplage avec différentes sources d’ionisation. L’électronébulisation (ESI), dans des conditions contrôlées d’ionisation, permet d’observer plus particulièrement les composés dérivés de la cellulose et de l’hémicellulose ainsi que des lipides et des dérivés de la lignine. La photoionisation à pression atmosphérique (APPI) et la désorption-ionisation par laser (LDI) sont plus spécifiques des espèces relatives à la lignine. Celles qui sont alors observées sont plus insaturées qu’en ESI. La complémentarité des différentes techniques d’analyse a été établie et a permis la description détaillée de bio-huiles. Cette méthodologie a été appliquée à des bio-huiles avant et après traitement de désoxygénation/cracking sur zéolithes. L’analyse par ESI FT-ICR MS a mis en évidence la sélectivité de ces catalyseurs envers les dérivés cellulosiques alors que l’étude par APPI et LDI a permis de déterminer la nature des composés obtenus après traitement catalytique. Ceux-ci présentent une diminution de la teneur en oxygène et résultent, pour une partie d’entre eux, du craquage catalytique sur les composés de la bio-huile originell

Next Challenges for the Comprehensive Molecular Characterization of Complex Organic Mixtures in the Field of Sustainable Energy

The conversion of lignocellulosic biomass by pyrolysis or hydrothermal liquefaction gives access to a wide variety of molecules that can be used as fuel or as building blocks in the chemical industry. For such purposes, it is necessary to obtain their detailed chemical composition to adapt the conversion process, including the upgrading steps. Petroleomics has emerged as an integral approach to cover a missing link in the investigation bio-oils and linked products. It relies on ultra-high-resolution mass spectrometry to attempt to unravel the contribution of many compounds in complex samples by a non-targeted approach. The most recent developments in petroleomics partially alter the discriminating nature of the non-targeted analyses. However, a peak referring to one chemical formula possibly hides a forest of isomeric compounds, which may present a large chemical diversity concerning the nature of the chemical functions. This identification of chemical functions is essential in the context of the upgrading of bio-oils. The latest developments dedicated to this analytical challenge will be reviewed and discussed, particularly by integrating ion source features and incorporating new steps in the analytical workflow. The representativeness of the data obtained by the petroleomic approach is still an important issue

Toward Controlled Ionization Conditions for ESI-FT-ICR-MS Analysis of Bio-Oils from Lignocellulosic Material

Pyrolysis or liquefaction processes can be applied to lignocellulosic biomass to produce a bio-oil which allows the access of green chemicals or sustainable energy. Among the different existing resources, this raw material has the advantage to come from nonfood feedstocks such as agricultural wastes (wood, grass, ...) or dedicated plantations. Whatever the considered bio-oil, the development of high performance analytical techniques is needed to achieve an exhaustive characterization. The use of Fourier transform ion cyclotron resonance mass spectrometry coupled to electrospray ionization (ESI-FT-ICR-MS) has the potential to chemically identify the components of bio-oil at the level of the molecular formula. In this work, we investigated the influence of the sample preparation (use and nature of dopant and ion detection mode) on the development of a robust methodology for lignocellulosic based bio-oil characterization. Commonly used ESI dopants have been studied to increase the ionization yield and the measurement repeatability. We highlighted the dramatic effect of the sample preparation on the global chemical description of the bio-oil, especially the disproportional contribution of the C_<i>x</i>H_<i>y</i>N_1–5O_<i>z</i> species. Moreover, we demonstrated the ability of well-controlled ESI ionization conditions to attain, on the one hand, specific chemical information on the origin (cellulose, hemicellulose, or lignin) of the bio-oil constituents and, on the other hand, the simultaneous description of both its oily and aqueous compounds without a fractionation step

Fractionation by flash chromatography and molecular characterization of bio-oil by ultra-high-resolution mass spectrometry and NMR spectroscopy

International audienceBio-oils obtained from the pyrolysis of lignocellulosic biomass are highly complex matrices with tens of thousands of organic compounds covering a wide polarity and mass range. Their upgrading into greener fuel or value-added chemicals requires an in-depth knowledge of their molecular composition prior and after valorization treatment, which can be obtained by different analytical techniques. Here, flash chromatography was employed as an efficient way to fractionate a bio-oil vacuum residue into four distinct fractions. This process was repeatable at both gravimetric and chromatographic levels and provided information about the weight contribution of each fraction to bio-oil composition. Achieved fractions were then characterized by ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and nuclear magnetic resonance spectroscopy. These two techniques ensured the good repeatability of bio-oil fractionation at the molecular level and also highlighted molecular specificities of each fraction. Thus, flash chromatography provided quantitative information that was complementary to FT-ICR MS results. It also simplifies the bio-oil compositional analysis, making it possible to detect more compounds. Eventually, this fractionation process can also be used to target fraction or compounds of interest for bio-oil upgrading