Heterogeneous Diels–Alder catalysis for biomass-derived aromatic compounds

In this study, oil palm empty fruit bunch (OPEFBF) was pretreated with alkali, and lignin was extracted for further degradation into lower molecular weight phenolic compounds using enzymes and chemical means. Efficiency of monomeric aromatic compounds production from OPEFBF lignin via chemical (nitrobenzene versus oxygen) and enzymatic [cutinase versus manganese peroxidase (MnP)] approaches was investigated. The effects of sodium hydroxide concentration (2, 5, and 10% wt.) and reaction time (30, 90, and 180 minutes) on the yield of aromatic compounds were studied. The results obtained indicated that nitrobenzene oxidation produced the highest yield (333.17 ± 49.44 ppm hydroxybenzoic acid, 5.67 ± 0.25 ppm p-hydroxybenzaldehyde, 25.57 ± 1.64 ppm vanillic acid, 168.68 ± 23.23 ppm vanillin, 75.44 ± 6.71 ppm syringic acid, 815.26 ± 41.77 ppm syringaldehyde, 15.21 ± 2.19 ppm p-coumaric acid, and 44.75 ± 3.40 ppm ferulic acid), among the tested methods. High sodium hydroxide concentration (10% wt.) was needed to promote efficient nitrobenzene oxidation. However, less severe oxidation condition was preferred to preserve the hydroxycinnamic acids (p-coumaric acid and ferulic acid). Cutinase-catalyzed hydrolysis was found to be more efficient than MnP-catalyzed oxidation in the production of aromatic compounds. By hydrolyzed 8% wt. of lignin with 0.625 mL cutinase g−1 lignin at pH 8 and 55°C for 24 hours, about 642.83 ± 14.45 ppm hydroxybenzoic acid, 70.19 ± 3.31 ppm syringaldehyde, 22.80 ± 1.04 ppm vanillin, 27.06 ± 1.20 ppm p-coumaric acid, and 50.19 ± 2.23 ppm ferulic acid were produced.

Biotechnological production of aromatic compounds of the extended shikimate pathway from renewable biomass

NAT-BENT, the production was 16.75%.This represents an approximate increase of 6.51% in hydrocarbon production with the use of PILL-BENT.Additionally, the production of aromatic compounds with PILL-BENT was 21.43%, compared to only 0.93% with NAT-BENT.This is a significant increase of approximately 20.5% in aromatic compound production.These results highlight the potential of PILL-BENT to improve the efficiency of hydrocarbon and aromatic compound production.Therefore, these results not only reinforce the feasibility of catalytic pyrolysis as a sustainable solution for plastic waste management but also underscore its potential to integrate into the circular economy, promoting sustainable development.This approach supports SDG 7, which aims to ensure sustainable and modern energy access.The conversion of plastic waste into alternative fuel reduces environmental impact and utilizes available resources, promoting a more sustainable future.

The genus Carum Rup. ex Linn. Syst. ed I. (1735) from the family Umbelliferae (= Apiaceae) comprises 195 species. In Europe five species grow: Carum carvi L., C. heldreichii Boiss., C. multiflorum (Sibth. et Sm.) Boiss., C. rigidulum (Viv.) Koch, ex DC, and C. verticillatum (L.) Koch. From the economical point of view, the most important is caraway, Carum carvi L. Sp. PL, 263 (1753), known also as Carum aromaticum Salisb., C. decussatum Gilib., C. officinale S.F. Gray, and C. careum Bub. (Index Kewensis 1895–1974).

Hydrothermal liquefaction of corn straw with mixed catalysts for the production of bio-oil and aromatic compounds

Specific molecular interactions between Vitis vinifera and Botrytis cinerea are required for noble rot development in grape berries

Biorefining Under Methane Atmosphere

The rules on regulating aromatic compounds production was investigated by aqueous catalytic reforming of sorbitol. It was found that aromatics, ketones, furans, organic acids were main compounds in organic phase. The obvious effect of metal content showed that the highest carbon selectivity of aromatics was 34.36% when 3wt% Ni content was loaded on HZSM-5 zeolite modified by MCM-41. However, it was decreased only to 4.82% when Ni content was improved to 20wt%. Meanwhile, different reaction parameters also displayed important impacts on carbon selectivity. It was improved with the increase of temperature, while it was decreased as liquid hourly space velocity and hydrogen pressure was increased. The results showed that appropriate higher temperature, longer contact time and lower hydrogen pressure were in favor of aromatics information, which suggested a feasible process to solve energy crisis.

The catalytic synthesis of 2,5-diformylfuran (DFF) from 5-hydroxymethylfurfural (HMF) attracts extensive attention in the research of biomass conversion. However, it is a challenge to achieve high conversion of HMF under mild conditions with a heterogeneous catalyst, which can be easily separated and recycled. Herein, we report a novel cobalt-based catalyst (CoxOy-N@TiO2) for the oxidation of HMF to DFF with 30 % aqueous tert-butyl hydroperoxide as the oxidant. A series of Co-based catalysts were prepared by a typical impregnation method, and detected by XRD, TEM and FT-IR techniques. Based on the experimental results of catalytic test, it is found that a 91 % conversion of HMF and 40 % selectivity of DFF was obtained with the CoxOy-N@TiO2 catalyst at 80 °C within 5 h. In addition, the CoxOy-N@TiO2 can be recycled up to five times without significant loss of activity. The efficient oxidation of 5-hydroxymethyl furfural, a biomass-derived platform compound, to produce 2,5-diformylfuran is achieved using CoxOy-N@TiO2 catalyst under mild conditions.

Supported metal catalysts are commonly used for the hydrogenation and deoxygenation of biomass-derived aromatic compounds in catalytic fast pyrolysis. To date, the substrate-adsorbate interactions under reaction conditions crucial to these processes remain poorly understood, yet understanding this is critical to constructing detailed mechanistic models of the reactions important to catalytic fast pyrolysis. Density functional theory (DFT) has been used in identifying mechanistic details, but many of these works assume surface models that are not representative of realistic conditions, for example, under which the surface is covered with some concentration of hydrogen and aromatic compounds. In this study, we investigate hydrogen-guaiacol coadsorption on Pt(111) using van der Waals-corrected DFT and ab initio thermodynamics over a range of temperatures and pressures relevant to bio-oil upgrading. We find that relative coverage of hydrogen and guaiacol is strongly dependent on the temperature and pressure of the system. Under conditions relevant to ex situ catalytic fast pyrolysis (CFP; 620-730 K, 1-10 bar), guaiacol and hydrogen chemisorb to the surface with a submonolayer hydrogen (~0.44 ML H), while under conditions relevant to hydrotreating (470-580 K, 10-200 bar), the surface exhibits a full-monolayer hydrogen coverage with guaiacol physisorbed to the surface. These results correlate with experimentally observed selectivities, which show ring saturation to methoxycyclohexanol at hydrotreating conditions and deoxygenation to phenol at CFP-relevant conditions. Additionally, the vibrational energy of the adsorbates on the surface significantly contributes to surface energy at higher coverage. Ignoring this contribution results in not only quantitatively, but also qualitatively incorrect interpretation of coadsorption, shifting the phase boundaries by more than 200 K and ~10-20 bar and predicting no guaiacol adsorption under CFP and hydrotreating conditions. We discuss the implications of this work in the context of modeling hydrogenation and deoxygenation reactions on Pt(111), and we find that only the models representative of equilibrium surface coverage can capture the hydrogenation kinetics correctly. Lastly, as a major outcome of this work, we introduce a freely available web-based tool, dubbed the Surface Phase Explorer (SPE), which allows researchers to conveniently determine surface composition for any one- or two-component system at thermodynamic equilibrium over a wide range of temperatures and pressures on any crystalline surface using standard DFT output.

Microbial cell factories for bioconversion of lignin to vanillin - Challenges and opportunities: A review.

The combined and sequential actions of a variety of microorganisms are responsible for the degradation of lignin in natural environments, with the transient production of low molecular weight aromatic compounds [1]. Among them, some guaiacol may be formed [2,3], and this by-product, when not further metabolized by the living organisms, can behave as a highly toxic agent inhibiting further microbial growth [4]. Despite the wealth of data available on the bacterial degradation of aromatic compounds [1,5,6], there is very little known about guaiacol as a substrate supporting bacterial growth [4,6]. We describe here a bacterial strain belonging to the genus Moraxel la that is capable of growing rapidly on guaiacol as the sole source of carbon and energy.

ABSTRACTTomato seed contains proteins of high nutritional value and nutraceutical properties, which can be recovered for application as food additives. In this study, we investigated the use of a Lactobacillus plantarum strain to obtain high-added-value peptides from the fermentation process using tomato seed meal extract as the substrate. Potentially tomato seed meal extract have antioxidant activity which is correlated to the amino acid structures, compositions and sequences. After 24 h of fermentation, the radical scavenging activity of the isolated extract was increased by 87%. The increase of antioxidant activity is potentially attributed to the production of different bioactive peptides bio transformed during fermentation. L. plantarum growth on tomato seed meal extract as substrate reduced content of crude and soluble proteins by 18.44% and 68.99%, respectively, after 24 h of fermentation. Gel filtration chromatography showed a depolymerization of high molecular weight of polymers. HPLC analysis showed a significant decrease in the concentration of total amino acids, especially glutamic acid and aspartic acid. FTIR results showed that the fermentation favors the production of new amides and aromatic compounds. The production of protease by L. plantarum was investigated and results showed that highest activity (401.45 U/ml) were obtained after 20 h of fermentation. Results confirmed that L. plantarum could degrade and convert tomato seed proteins into bioactive peptides that contributed positively to the improvement of antioxidant activity of the protein isolate.

Ο καφές αποτελεί ένα από τα πλέον προσφιλή ροφήματα παγκοσμίως και αυτό δικαιολογεί, σε μεγάλο βαθμό, το γεγονός ότι βρίσκεται στο επίκεντρο του επιστημονικού ενδιαφέροντος εδώ και πολλές δεκαετίες. Η κατά κεφαλή κατανάλωση ροφημάτων καφέ σημειώνει αύξηση κάθε χρόνο και, σύμφωνα με τα διαθέσιμα στοιχεία, τα πρωτεία έχουν η Φινλανδία, η Νορβηγία και η Ισλανδία, ακολουθούμενες από τη Δανία, την Ολλανδία και τη Σουηδία. Η οικονομική και εμπορική σημασία του καφέ είναι πολύ μεγάλη, καθώς αποτελεί το σημαντικότερο γεωργικό εμπόρευμα, μετά το πετρέλαιο. Η δημοτικότητα του καφέ οφείλεται κυρίως στα μοναδικά οργανοληπτικά χαρακτηριστικά, αλλά και στην ήπια διεγερτική δράση του ροφήματος που αποδίδεται στην παρουσία καφεΐνης και παρόμοιων ενώσεων. Ο καφές παράγεται από τα σπέρματα καφεόδεντρων που ανήκουν στο γένος Coffea της οικογένειας Rubiaceae, μιας από τις μεγαλύτερες οικογένειες ανθοφόρων φυτών, με 500 περίπου γένη και 6.000 είδη. Από το σύνολο των διαφορετικών ειδών, πλέον σημαντικά από οικονομική άποψη είναι τα Coffea arabica L., και Coffea canephora var. robusta. Η μοναδική ταυτότητα των διαφορετικών ποικιλιών καφέ αρχίζει να διαμορφώνεται κατά την ανάπτυξη του φυτού, καθώς και στη διάρκεια των μετασυλλεκτικών χειρισμών και των διαδικασιών που έπονται της συγκομιδής των καρπών. Περιβαλλοντικοί παράγοντες, όπως η γεωγραφική προέλευση, το κλίμα, το υψόμετρο, η θερμοκρασία και η θρέψη του φυτού, επηρεάζουν σημαντικά την ποιότητα του καφέ. Ιδιαίτερα καθοριστική θεωρείται επίσης η δράση ενζύμων σε συστατικά των σπερμάτων, όπως οι πρωτεΐνες, οι υδατάνθρακες και οι φαινολικές ενώσεις. Σημαντικό ρόλο στη διαδικασία αυτή διαδραματίζουν μικροοργανισμοί (ζύμες, βακτήρια, μύκητες), οι οποίοι παράγουν πληθώρα μεταβολικών προϊόντων, κυρίως αλκοόλες και οξέα. Ο χαρακτήρας του καφέ τροποποιείται περαιτέρω κατά τη φρύξη (καβούρδισμα), στη διάρκεια της οποίας κυριαρχούν αντιδράσεις Maillard, οδηγώντας στην παραγωγή αρωματικών και γευστικών ενώσεων. Τα αρωματικά συστατικά που παράγονται κατά το καβούρδισμα συνιστούν, χωρίς αμφιβολία, τον πιο καθοριστικό παράγοντα της ποιότητας του καφέ. Οι πτητικές ενώσεις χαρακτηρίζουν όχι μόνο τις διαφορετικές ποικιλίες, αλλά και τη γεωγραφική προέλευση του καφέ. Μέχρι σήμερα, έχουν προσδιοριστεί περισσότερα από 1.000 πτητικά συστατικά. Εντούτοις, λίγα εξ αυτών φαίνεται να είναι σημαντικά για το άρωμα και τη γεύση του καφέ. Σύμφωνα με ορισμένους ερευνητές, το ιδιάζον άρωμα ενός τύπου καφέ διαμορφώνεται, ως επί το πλείστον, από μια ομάδα 20-30 μεμονωμένων πτητικών συστατικών

In fast catalytic pyrolysis of eucalyptus as woody biomass, zeolites enhanced the formation of aromatic hydrocarbons with and without O-atoms, mainly. H-ZSM-5 and H-Beta zeolites were efficient for the formation of non-oxygenated aromatic compounds. High Si/Al2 ratio in H-ZSM-5 depressed the formation of non-oxygenated aromatics, while high Si/Al2 ratio in H-Beta kept high yield of non-oxygenated aromatics. H-mordenite and USY showed a moderate catalytic activity for the formation of phenolic compounds as well as non-oxygenated aromatics, due to moderate catalytic properties. Aromatic compounds may be derived from cellulose, hemicellulose and lignin. In the case of cellulose or hemicellulose as source of aromatics, oxygenated intermediates were formed by thermal decomposition of cellulose or hemicellulose, followed by reaction to form aromatic compounds. In the case of lignin source, oxygenated aromatics were formed by thermal decomposition of lignin, followed by deoxygenation to form non-oxygenated aromatics. Strong solid acidity favors deoxygenation reaction. Moderate solid acidity leads to the formation of phenolic compounds. Large micropore diameter and 3-dimensional microstructure have advantage, since intermediates can contact active sites inside the micropore. Except for SAPO-34, 4A, 13X and Ti-silicate, exhibiting significantly low yield of both of non-oxygenated aromatics and phenols, there seems to be an inversed correlation between yield of non-oxygenated aromatic compounds and that of phenolic compounds.