Descripción de la oferta de empleo

Overview: This is a 3-year PhD scholarship offer. This project will focus on the transformation of hydrolysates from lignocellulosic biomass to bioplastics and value-added chemicals that are important platform compounds in chemical industry. The project will proceed with the catalytic and microbiological/enzymatic reactions on biomass products and their analysis. Background and State of the Art: This project proposal aims at the valorisation of the other platform chemicals that are derived from the hydrolysis of lignocellulosic materials. We propose a combination of catalytic and biological treatments to obtain industrially-relevant commodity chemicals. Enormous research efforts have been performed to find new catalytic processes, for obtaining economically viable lignocellulosic-derived fuels and chemicals. However, less attention has been paid, for instance, to the use of hydrotalcite-like catalytic materials (HTs), as well as together with the use of microwave reactors. Our group has a large experience in the field of hydrotalcite-like materials (more than 30 papers published in this field) and has been tested different catalytic reactions such as hydrogenation, aldol condensation, oxidation, isomerization, etc. The objective of VALORA is to study the use of hydrotalcite-like materials as catalyst combined with the use of microwave reactor for the valorisation of products obtained by the hydrolysis of lignocellulose materials. For instance, the transformation of levulinic acid, HMF and FUR to diols by hydrogenation. Also, aldol condensation reactions for furfural, HMF and pentanones with acetone, catalysed by hydrotalcites as well, but assisted by microwave reactors. In this process, the C8 to C15 adducts obtained from the condensation process will be transformed upon hydrogenation or after a deep dehydrodeoxygenation step into jet fuel range alkanes. On the other hand, photocatalyst from hydrotalcite-like materials will be applied to HMF to obtain FDCA (2,5-furandicarboxylic acid) and FDC (2,5-furandicarboxaldehyde). Most of the chemical reactions will be assisted by microwave and results compared to conventional reactors. Microwave irradiation has several advantages over conventional reactors, which include a) faster reactions (in a few minutes), b) higher uniformity in conditions and enhanced selectivity and c) lower energy requirements (Mood et al, ). Furthermore, in this project, a new process based on olefin metathesis to produce adipic acid from levulinic acid will be also developed. On the other hand, in VALORA project, biological reactions will be also applied for the conversion of hydrolysates in the same crude hydrolysis broth. For instance, levulinic acid will be transformed to polyhydroxyalkanoates (PHA co-polymer) and in the same way, xylose can be converted to PHB (polyhydroxybutyrate), which display mechanical properties similar to those of polypropylene, a petroleum-derived plastic. In another embodiment, FUR will undergo enzymatic conversion to furoic acid, via lipase-mediated in situ formation of peracids, which selectively oxidize aldehydes to carboxylic acids. These reactions will be conducted with pure chemical substrates, as well as with the (crude) hydrolysis broth coming from lignocellulose components. The aim is to demonstrate that the used (bio)catalysts may perform useful transformations under real conditions, what in turn would save costs associated to downstream units, as no purification steps would be required in the biorefinery. Apart from these (hemi)cellulose-derived compounds, this proposal will go beyond by tackling lignin valorisation as well. Thus, in the finalizing project, a cellulose-lignin fraction was obtained after walnut shell autohydrolysis of hemicellulose. In VALORA, this fraction will be the starting point for further valorisation strategies (e.g. chemical oxidation of lignin). To this end, emerging methods to dissolve lignin and separate it from cellulose will be implemented, such as the use of some Deep Eutectic Solvents (DES). Once lignin is separated from cellulose using DES, chemical valorisation of the obtained lignin will be conducted as well. Overall, VALORA will have the ambitious (but realistic) aim of valorising all fractions of lignocellulose, with emphasis both in the (pre)treatment methods for separating the components, as well as in the setup of novel (bio)catalytic approaches to afford industrially-sound platform chemicals. Thus, the majority of the compounds present in the hydrolysates will be transformed and consequently waste from biomass residues will be reduced, fulfilling the postulates of the circular bio-based economy. Project Contribution and Methodology: Conventional chemical reactions on biomass hydrolysates are the most common treatments found in bibliography. However, in this work, a new process using microwave reactor will make the reactions faster and more selective. In addition, biological transformations will be applied. Substrates and products of both processes will be characterized with TOC (total organic carbon), HPLC (high performance liquid chromatography), GC (gas chromatography), XRD (X‐ray diffraction) and SEM (scanning electron microscopy) and fermentations will be carried out with conventional microbiological methods. As a result, different end products will be obtained such as PHB and FDCA (plastics), furoic acid (important in food industry and nylon preparation), C5-C8 alkanes (for jet fuel), adipic acid (for Nylon 66) and so on, all of them with potential industrial applications. The ideal candidate: It is desirable that the candidate has a degree in Chemical Engineering, Biotechnology, Chemistry, Microbiology or Bioengineering. A good level of oral and written English is required. References: Ahorsu R, Cintorrino G., Medina F., Constantí M. Microwave processes: a viable technology for obtaining xylose from walnut shell to produce lactic acid by Bacillus coagulans. J. Cleaner Production. In press. Ahorsu R, Medina F., Constantí M. Significance and challenges of biomass as a suitable feedstock for bioenergy and biochemical production: a review. Energies, . Blumer-Schuette SE, Kataeva Irina; Westpheling Janet; et al. Extremely thermophilic microorganisms for biomass conversion: status and prospects. CURRENT OPINION IN BIOTECHNOLOGY . Chimentao RJ., Lorente E., Gispert-Guirado F., Medina F., López F. Hydrolysis of dilute acid-pretreated cellulose under mild hydrothermal conditions. Carbohydrate polymers . Fukuoka A., P.L. Dhepe, Catalytic Conversion of Cellulose into Sugar Alcohols. Angew. Chem., Int. Ed. . Gavilà L., Constantí M. and Medina F. D-Lactic acid production from cellulose: dilute acid treatment of cellulose assisted by microwave followed by microbial fermentation. Cellulose . Gavilà L, Constantí M, Medina F. Dilute acid hydrolysis of cellulose assisted my microwave: how chlorine and irradiation time play an important role. IJES, . Gavilà L, Constantí M, Medina F, Pezoa-Conte R, Anugwom I, Mikkola J-P. Lactic acid production from renewable feedstock: fractionation, hydrolysis, and fermentation. Adv Sustainable Syst. (. Guarin C, Gavilà L, Constantí M, Medina F. Impact of cellulose treatment with hydrotalcites in hydrothermal catalytic conversion. Chem Eng Sci . Güell E.J., Maru B. T., Chimentão R. J., Gispert-Guirado F., Constantí M., and Medina F. Combined heterogeneous catalysis and dark fermentation systems for the conversion of cellulose into biohydrogen. Biochemical Engineering Journal . Ishikawa Y., S. Saka, Cellulose (Dordrecht, Netherlands) . Maru B, Constanti M, Stchigel AM, Medina F, Sueiras JE. Biohydrogen production by dark fermentation of glycerol using Enterobacter and Citrobacter sp. Biotechnology Progress . Maru B, Bielen A.A.M., Constantí M., Medina F., Kengen S.W.M. Glycerol fermentation to hydrogen by Thermotoga maritima: proposed pathway and bioenergetics considerations. Accepted for its publication in Int. J Hydrogen Energy, . Sims R. Biomass and resources bioenergy options for a cleaner environment in developed and developing countries. Elsevier Science, London, UK, . Sjöström E. . Wood Chemistry: fundamentals and applications. Academic Press, San Diego, USA. PROJECT SUPERVISORS Name: Dr. Francesc Medina, Dr. Magdalena Constantí e-mail:   Telephone: +   (c) , Doctoral and Master Studies in Nanoscience, Materials and Chemical Engineering, Universitat Rovira i Virgili  
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Detalles de la oferta

  • Universitat Rovira i Virgili - Dept. Chemical Engineering
Fecha de publicación
  • 23/07/2019
Fecha de expiración
  • 21/10/2019