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Use of scavengers in the pretreatment of lignocellulosic biomass for improved chemicals production

English title Use of scavengers in the pretreatment of lignocellulosic biomass for improved chemicals production
Applicant Rudolf von Rohr Philipp
Number 136709
Funding scheme NRP 66 Resource Wood
Research institution Institut für Verfahrenstechnik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Chemical Engineering
Start/End 01.01.2012 - 30.06.2017
Approved amount 628'687.00
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Keywords (6)

Scavenger; Pretreatment; Biofuels; Lignin; Enzymatic hydrolysis; Lignocellulose

Lay Summary (German)

Lead
Kombinierte Herstellung von Treibstoffen und Chemikalien aus Holz Im Mittelpunkt dieses Projekts steht ein neuartiger Ansatz, um Holz für die Produktion von Treibstoffen und Chemikalien vorzubehandeln. Die Forschenden kombinieren dabei den Heisswasseraufschluss mit dem Einsatz sogenannter Radikalfänger.
Lay summary

Hintergrund
Biotreibstoffe aus Holz haben im Vergleich zu solchen aus Maisstärke oder Zuckerrohr wirtschaftliche und ökologische Vorteile (Kosten, Verfügbarkeit, keine Konkurrenz zu Nahrungsmittelproduktion). Holz lässt sich jedoch deutlich schwieriger zu Biotreibstoffen umwandeln. Denn im Holz sind die Komponenten Cellulose, Hemicellulose und Lignin stark miteinander verflochten, unter anderem um die Pflanze gegen äussere Einflüsse zu schützen. Bei der Herstellung von Biotreibstoffen behindert dies den enzymatischen Abbau von Cellulose und Lignocellulose zu ihren Zuckern, die anschliessend beispielsweise zu Bioethanol vergärt werden können. Daher ist es notwendig, das Holz vorzubehandeln, um dessen Struktur aufzubrechen und den enzymatischen Zugang zu verbessern.

Ziel
Eine mögliche Vorbehandlung der Biomasse stellt ein Heisswasseraufschluss dar, den jedoch Vernetzungsreaktionen von entstehenden Ligninfragmenten behindern. Sogenannte "Radikalfänger" können diese unerwünschten Reaktionen unterbinden und den Aufschluss des Holzes wesentlich verbessern. Dieses Verfahren soll es ermöglichen, einerseits eine Cellulosefraktion mit verbessertem enzymatischen Zugang zu erzeugen und andererseits eine hochwertige Ligninfraktion entstehen zu lassen. Diese dient dann als Ausgangsmaterial für die Herstellung aromatischer Chemikalien.

Bedeutung
Das untersuchte Verfahren zielt auf die Produktion von Treibstoffen und aromatischen Chemikalien ab, die heute noch aus petrochemischen Ressourcen gewonnen werden. Damit eröffnen sich neue Möglichkeiten, Erdöl mehr und mehr durch Biomasse zu ersetzen.

Direct link to Lay Summary Last update: 29.01.2013

Lay Summary (French)

Lead
Fabrication combinée de carburants et de produits chimiques à partir de bois Une approche innovante de prétraitement du bois pour la production de carburants et de substances chimiques constitue le cœur de ce projet. Les chercheurs y combinent le prétraitement à l’eau chaude au recours à des "pièges à radicaux".
Lay summary

Contexte
Comparés aux biocarburants issus de l’amidon de maïs ou du sucre de canne, les biocarburants d’origine ligneuse présentent de nombreux atouts sur le plan économique et écologique (coûts, disponibilité et absence de concurrence avec la production d’aliments). En revanche, la transformation du bois en biocarburant s’avère beaucoup plus délicate. En effet, les constituants du bois tels que la cellulose, les hémicelluloses et la lignine sont étroitement enchevêtrés, notamment pour protéger la plante des influences extérieures. Lors de la production de biocarburant, cela empêche la dégradation enzymatique de la cellulose et de la lignocellulose en sucres, pouvant ensuite être distillés en bioéthanol. Un prétraitement du bois s’impose donc, afin d’en éclater la structure et d’améliorer l'accès enzymatique.

But
La préparation à l’eau chaude est une des solutions potentielles de prétraitement de la biomasse, qui est toutefois entravée par des réactions de réticulation des fragments de lignine. Les "pièges à radicaux" peuvent parer à ce phénomène indésirable et optimiser nettement le traitement initial du bois. Ce procédé est d’une part destiné à générer une fraction de cellulose à accès enzymatique amélioré et d’autre part à produire des fractions de lignine de grande qualité. Celle-ci sert alors de matériau de départ pour l’élaboration de substances chimiques aromatiques.

Portée
Le procédé étudié vise la production de carburants et de substances chimiques aromatiques qui proviennent actuellement de ressources pétrochimiques. Il ouvre de nouvelles possibilités de remplacement progressif du pétrole par la biomasse.

Direct link to Lay Summary Last update: 29.01.2013

Lay Summary (English)

Lead
Combined production of fuels and chemicals from wood This project examines an innovative approach for pre-treating wood in order to produce fuels and chemicals. In this approach, the researchers combine hot water treatment with so-called radical scavengers.
Lay summary

Background
Biofuels from wood have economic and ecological advantages as compared to fuels from corn starch and sugar cane (costs, availability, no conflict with food production). However, it is much more difficult to transform wood into biofuels. This is because the components of wood—cellulose, hemicelluloses and lignin—are strongly interwoven to protect the plant against external forces, in particular. In the production of biofuels, this impedes the enzymatic degradation of cellulose and lignocellulose into their respective sugars, which can subsequently be fermented to produce, for example, bio-ethanol. Therefore, it is necessary to pre-treat the wood in order to break up its structure and improve the enzymatic access.

Aim
One possible treatment of biomass would be to dissolve it in hot water, but this is hampered by cross-linking reactions of emerging lignin fragments. So-called "radical scavengers" can stop these undesired reactions and make the wood much more soluble. This procedure is aimed at achieving, on the one hand, a cellulose fraction with improved enzymatic access and, on the other hand, a high-quality lignin fraction. The latter serves as a starting material for the production of aromatic chemicals.

Significance
The examined approach is aimed at producing fuels and aromatic chemicals which are today still gained from petrochemical resources. This opens up new avenues for gradually replacing fossil oil with biomass.

Direct link to Lay Summary Last update: 29.01.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Autohydrolysis pretreatment of softwood – enhancement by phenolic additives and the effects of other compounds
Pielhop Thomas, Larrazábal Gastón O., Rudolf von Rohr Philipp (2016), Autohydrolysis pretreatment of softwood – enhancement by phenolic additives and the effects of other compounds, in Green Chemistry, 18(19), 5239-5247.
Steam explosion pretreatment of softwood: the effect of the explosive decompression on enzymatic digestibility
Pielhop Thomas, Amgarten Janick, Rudolf von Rohr Philipp, Studer Michael H (2016), Steam explosion pretreatment of softwood: the effect of the explosive decompression on enzymatic digestibility, in Biotechnology for Biofuels, 9(1), 1-13.
Lignin repolymerisation in spruce autohydrolysis pretreatment increases cellulase deactivation
Thomas Pielhop, Gastón O. Larrazábal, Michael H. Studer, Simone Brethauer, Christoph-M. Seidel, Philipp Rudolf von Rohr (2015), Lignin repolymerisation in spruce autohydrolysis pretreatment increases cellulase deactivation, in Green Chemistry, 17(6), 3521-3532.

Collaboration

Group / person Country
Types of collaboration
ETH Zürich, Prof.Dr. Konrad Hungerbühler Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
PSI, Dr. Frédéric Vogel Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
Berner Fachhochschule, Dr.Michael Studer Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Industry/business/other use-inspired collaboration

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
4TH SYMPOSIUM ON BIOTECHNOLOGY APPLIED TO LIGNOCELLULOSES (LIGNOBIOTECH IV) Talk given at a conference STEAM EXPLOSION PRETREATMENT OF LIGNOCELLULOSIC BIOMASS – THE EFFECT OF THE EXPLOSION ON ENZYMATIC DIGESTIBILITY 19.06.2016 Madrid, Spain Rudolf von Rohr Philipp; Pielhop Thomas; Seidel Christoph-Maximilian;
3rd European Congress of Applied Biotechnology (ECAB3) Talk given at a conference Use of carbocation scavengers in the steam-explosion pretreatment of spruce wood 27.09.2015 Nice, France Seidel Christoph-Maximilian;
3rd International Symposium on Green Chemistry (ISGC 2015) Poster Use of carbocation scavengers in the pretreatment of spruce wood 03.05.2015 La-Rochelle, France Seidel Christoph-Maximilian;
4th International Conference On Lignocellulosic Ethanol Talk given at a conference Use of carbonium ion scavengers in the hot water pretreatment of spruce wood 23.09.2014 Landshut, Germany Seidel Christoph-Maximilian; Pielhop Thomas;
5th International Conference on Engineering for Waste and Biomass Valorisation (WasteEng) Talk given at a conference Use of carbocation scavengers in the hot water pretreatment of spruce wood 25.08.2014 Rio de Janeiro, Brazil Rudolf von Rohr Philipp;
36th Symposium on Biotechnology for Fuels and Chemicals (SBFC) Talk given at a conference Use of carbonium ion scavengers in the hot water pretreatment of spruce wood 28.04.2014 Clearwater Beach, United States of America Pielhop Thomas;
9th World Congress of Chemical Engineering Talk given at a conference Carbonium Ion Scavengers in the Pretreatment of Wood for Biofuel Production 19.08.2013 Seoul, Korean Republic (South Korea) Pielhop Thomas; Rudolf von Rohr Philipp;
PSC Symposium 2012 „Plants Replacing Fossil Fuels?“ Poster Carbonium Ion Scavengers in the Pretreatment of Wood for Biofuel Production 08.11.2012 Zürich, Switzerland, Switzerland Pielhop Thomas;
EWLP 2012, 12th European workshop on Lignocellulosics and Pulp Talk given at a conference Use of Carbonium Ion Scavenger in the Pretreatment of Spruce Wood 27.08.2012 Helsinki, Finnland, Finland Rudolf von Rohr Philipp; Pielhop Thomas;


Knowledge transfer events

Active participation

Title Type of contribution Date Place Persons involved
Dialogue platform "Novel ways in bio-refining of wood" Talk 10.12.2015 Bern, Switzerland Pielhop Thomas; Rudolf von Rohr Philipp;


Communication with the public

Communication Title Media Place Year
Media relations: print media, online media Mehr Zucker aus Holz ETH News International 2014
New media (web, blogs, podcasts, news feeds etc.) Swiss researchers make breakthrough in cellulose pre-treatment BiofuelsDigest International 2014

Awards

Title Year
Poster Award, PSC Symposium 2012 „Plants Replacing Fossil Fuels?“ 2012

Patents

Abstract

Second generation biofuels (e.g. bioethanol) produced from lignocellulosic materials, show energetic, economic and environmental advantages in comparison to biofuels from starch or sugar. However, physical and chemical barriers caused by the entanglement of the main components of lignocellulosic biomass, hinder the hydrolysis of cellulose and hemicellulose to fermentable sugars (Alvira & Tomás-Pejó et al., 2010). Therefore, pretreatment steps for lignocellulosic biomass aim at breaking down the lignin structure and disrupting the crystallinity of cellulose to enhance enzyme accessibility to the cellulose during the hydrolysis step (Mosier & Wyman et al., 2005). The lignin fraction is thereby generally regarded as a potential energy source or as feedstock for the production of arenes due to its aromatic structure. So far however, the breakthrough for a process converting lignins into higher value base chemicals is still pending.Most of the approaches of lignin utilisation deal with lignins arising as a byproduct from certain processes like pulping or pretreatment fractionation. On the other hand, studies on bioethanol production from lignocellulosic biomass basically aim at modifying the lignin fraction for an improved enzymatic hydrolysis but not on lignin exploitation. We suggest a more integrative approach, which allows for the valorisation of cellulose as well as lignin. The valorisation of both fractions will be taken into account from the beginning, which means already at the pretreatment step of lignocellulosic biomass. We propose the use of scavengers for carbonium ions that are formed in the pretreatment, which can both enhance delignification and allow the production of a well-defined pre-degraded lignin fraction to be exploited in a further reaction step.The main objective of the project is to devise a process, which yields a highly digestible (ligno)cellulose for enzymatic hydrolysis and a high quality lignin fraction at the same time.
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