PRIN LEVANTE 2020: Levulinic acid valorization through advanced novel technologies

The project LEVANTE deals with the development of new catalytic processes for the valorization of levulinic acid and its esters towards three classes of compounds: levulinic ketals, diphenolic acid and γ-valerolactone together with other reduction products

Levulinic acid production from the green macroalgae chaetomorpha linum and valonia aegagropila harvested in the orbetello lagoon

In recent years, the replacement of fossil resources with renewable ones has received great interest, especially as regards the production of new valuable bio-products and bio-fuels, in order to replace the traditional petroleum-based ones. In this context, the exploitation of waste biomasses into added-value biochemicals is strongly encouraged. Among these ones, the algae ones are attracting considerable attention, in particular macroalgae which cause eutrophication problems in estuaries and lagoons, due to the drastic reduction of dissolved oxygen during their decomposition. This is true for Orbetello lagoon (Italy), where a large amount of algal biomasses is removed every year through an expensive practice, with consequent environmentally serious disposal problems. In this work, for the first time, the acid-catalyzed conversion of two different macroalgae harvested in Orbetello lagoon, Chaetomorpha linum (Muller) Kutzing and Valonia aegagropila C. Agardh, into levulinic acid was studied and optimized, adopting a one-pot hydrothermal treatment, under microwave heating and in the presence of aqueous diluted mineral acids, H2SO4 and HCl. Levulinic acid is a versatile platform chemical, classified by the United States Department of Energy as one of the top-12 promising bio-based building blocks. The effect of the main reaction parameters to give levulinic acid was investigated and discussed, in particular the type and concentration of the acid catalyst, the temperature and the reaction time. The highest levulinic acid yields of 19 wt% for Chaetomorpha linum and 16 wt% for Valonia aegagropila, calculated respect to the weight of the starting dried biomass, were reached. The achieved results are very promising and confirm the significant potential of these green algae as renewable starting feedstocks for levulinic acid production

Sustainable exploitation of residual cynara cardunculus l. To levulinic acid and n-butyl levulinate

Hydrolysis and butanolysis of lignocellulosic biomass are efficient routes to produce two valuable bio-based platform chemicals, levulinic acid and n-butyl levulinate, which find increasing applications in the field of biofuels and for the synthesis of intermediates for chemical and pharmaceutical industries, food additives, surfactants, solvents and polymers. In this research, the ac-id-catalyzed hydrolysis of the waste residue of Cynara cardunculus L. (cardoon), remaining after seed removal for oil exploitation, was investigated. The cardoon residue was employed as-received and after a steam-explosion treatment which causes an enrichment in cellulose. The effects of the main reaction parameters, such as catalyst type and loading, reaction time, temperature and heat-ing methodology, on the hydrolysis process were assessed. Levulinic acid molar yields up to about 50 mol % with levulinic acid concentrations of 62.1 g/L were reached. Moreover, the one-pot bu-tanolysis of the steam-exploded cardoon with the bio-alcohol n-butanol was investigated, demon-strating the direct production of n-butyl levulinate with good yield, up to 42.5 mol %. These results demonstrate that such residual biomass represent a promising feedstock for the sustainable production of levulinic acid and n-butyl levulinate, opening the way to the complete exploitation of this crop

Multi-step exploitation of raw arundo donax L. For the selective synthesis of second-generation sugars by chemical and biological route

Lignocellulosic biomass represents one of the most important feedstocks for future biorefineries, being a precursor of valuable bio-products, obtainable through both chemical and biological conversion routes. Lignocellulosic biomass has a complex matrix, which requires the careful development of multi-step approaches for its complete exploitation to value-added compounds. Based on this perspective, the present work focuses on the valorization of hemicellulose and cellulose fractionsof giant reed (Arundo donax L.) to give second-generation sugars, minimizing the formation of reaction by-products. The conversion of hemicellulose to xylose was undertaken in the presence of the heterogeneous acid catalyst Amberlyst-70 under microwave irradiation. The effect of the main reaction parameters, such as temperature, reaction time, catalyst, and biomass loadings on sugars yield was studied, developing a high gravity approach. Under the optimised reaction conditions (17 wt% Arundo donax L. loading, 160 °C, Amberlyst-70/Arundo donax L. weight ratio 0.2 wt/wt), the xylose yield was 96.3 mol%. In the second step, the cellulose-rich solid residue was exploited through the chemical or enzymatic route, obtaining glucose yields of32.5 and56.2 mol%, respectively. This work proves the efficiency of this innovative combination of chemical and biological catalytic approaches, for the selective conversion of hemicellulose and cellulose fractions of Arundo donax L. to versatile platform products

Sustainable exploitation of paper mill wastes: a resource to re-use in the paper factory

In the papermaking industry, billions of tonnes of paper mill wastes are globally produced as wastes every year. These include cellulosic and inorganic sludges, which are traditionally landfilled, leading to environmental and economic issues. For these reasons, it is urgent to develop new sustainable strategies to exploit these fractions. Up to now, these sludges have been exploited i) for land application (as soil amendment/substrate), ii) for energy recovery and iii) for the production of bio-composites. However, the above possibilities involve the direct use of the bulk wastes, without fractionating/exploiting each feedstock component. In the perspective of the valorisation of the different components, the present investigation has considered different strategies: i) a thermal treatment, ii) an alkaline and iii) a mechanical one, aimed at the fractionation and recovery of the two main components of cellulosic and inorganic sludge, cellulose and calcium carbonate, respectively, that could be advantageously reused within the same papermaking process

Biomass ethanolysis: process optimization and performances of ethyl levulinate as diesel blendstock

Biomass represents a key asset for renewable energy production in the context of the more and more pressing energetic transition. Moreover, at the present, the issue of how to store a convenient amount of energy on board of electric vehicles is still a challenge and electric vehicles perspectives are limited to passenger cars and very small-range trucks, significant amount of time being necessary to define the eventual appropriate electric storage system to be employed in heavy transport, as well in aviation and shipping. In this context alkyl levulinates represent a concrete perspective for partial replacement of fossil fuel with renewable blendstocks. In particular, ethyl levulinate (EL) production by direct acid-catalyzed biomass ethanolysis was studied in order to investigate and optimize this one-step process which involves only renewable starting materials (biomass and bioethanol). In this perspective, the role of the main reaction parameters as the substrate nature and loading, type of the acid catalyst and its concentration, reaction temperature and duration were studied. EL was tested up to high concentrations in a mixture with diesel fuel in a small single-cylinder air-cooled diesel engine, to verify the engine and emission performances of the different blend compositions respect to those ascertained with a conventional diesel fuel

Electro-oxidative depolymerisation of technical lignin in water using platinum, nickel oxide hydroxide and graphite electrodes

In order to improve the lignin exploitation to added-value bioproducts, a mild chemical conversion route based on electrochemistry was investigated. For the first time, soda lignin Protobind™ 1000 (technical lignin from the pulp & paper industry) was studied by cyclic voltammetry to preliminarily investigate the effect of the main reaction parameters, such as the type of electrode material (platinum, nickel oxide hydroxide, graphite), the pH (12, 13, 14), the scan rate (10, 50, 100, 250 mV s-1), the substrate concentration (2, 20 g L-1) and the oxidation/reduction potential (from -0.8 to +0.8 V). Under the optimal reaction conditions among those tested (NiOOH electrode, pH 14, lignin 20 g L-1, 0.4 V), the electro-oxidative depolymerisation of lignin by electrolysis was performed in a divided cell. The reaction products were identified and quantified by ultra-pressure liquid chromatography coupled with mass spectrometry. The main products were sinapic acid, vanillin, vanillic acid, and acetovanillone. The obtained preliminary results demonstrated the potential feasibility of this innovative electrochemical route for lignin valorisation for the production of bio-aromatic chemicals

A novel organosolv approach to allow efficient biomass fractionation and successive exploitation

The separation and exploitation of all three main components of lignocellulosic biomass represents a challenging target for biorefinery. In this perspective a novel strategy has been studied for the fractionation and integral exploitation of Arundo Donax L. biomass, a feedstock characterized by low cost, large availability, favourable composition and ability to grow in marginal lands unsuitable for agriculture, avoiding any competition with food chain. The adoption of n-butanol played a fundamental dual role: as fractionation organosolv agent to separate cellulose, hemicellulose, and lignin and also as reagent for the conversion of the obtained cellulose fraction to n-butyl levulinate. A preliminary hot water pre-treatment of the biomass for reducing the content of extractives makes the separation even more effective. A preliminary optimization of the main reaction conditions was performed

CD200 as a Potential New Player in Inflammation during Rotator Cuff Tendon Injury/Repair: An In Vitro Model

Rotator cuff tendon (RCT) disease results from multifactorial mechanisms, in which inflammation plays a key role. Pro-inflammatory cytokines and tendon stem cell/progenitor cells (TSPCs) have been shown to participate in the inflammatory response. However, the underlying molecular mechanism is still not clear. In this study, flow cytometry analyses of different subpopulations of RCT-derived TSPCs demonstrate that after three days of administration, TNFα alone or in combination with IFNγ significantly decreases the percentage of CD146+CD49d+ and CD146+CD49f+ but not CD146+CD109+ TSPCs populations. In parallel, the same pro-inflammatory cytokines upregulate the expression of CD200 in the CD146+ TSPCs population. Additionally, the TNFα/IFNγ combination modulates the protein expression of STAT1, STAT3, and MMP9, but not fibromodulin. At the gene level, IRF1, CAAT (CAAT/EBPbeta), and DOK2 but not NF-κb, TGRF2 (TGFBR2), and RAS-GAP are modulated. In conclusion, although our study has several important limitations, the results highlight a new potential role of CD200 in regulating inflammation during tendon injuries. In addition, the genes analyzed here might be new potential players in the inflammatory response of TSPCs