SUSBIND MAKES A SUCCESSFUL YEAR RECAP WITH NEW TECH TOWARDS THE GREEN DEAL

SUSBIND’s collaborative partnership of six research and five industry partners from the EU has made substantial progress this year in developing highly sustainable bio-based binders that will in future replace conventional fossil-based ones currently used for wood-based panel boards in furniture mass products.

Towards the Green Deal

The SUSBIND binder aims at containing a significantly lower carbon footprint, while also reducing formaldehyde emissions and thus making a meaningful contribution in improving the public health and helping mitigate climate change. Hand in hand with the Green Deal targets, SUSBIND also provides cutting-edge clean technological innovation by converting carbohydrates and vegetable oils to binder precursors by “mild” technologies, i.g. by converting carbohydrates to Hydroxymethylfurfural (HMF) and vegetable oils and derivates to epoxides.

SUSBIND adhesive and board samples

New alternative technology to incumbent adhesives

As recently suggested by the Scientific Coordinator, Massimo Bregola of Cargill, at the EFIB conference in Oct in Vienna, Austria the wood board industry of today delivers excellent results both in terms of economic, environmental and social perspectives as consequences of decades of process improvement. A completely new alternative to incumbent adhesive technology is a challenge which requires dedication and collaboration across the whole supply chain.

The European carbohydrate market shows the potential to play an important role as a significant source of alternative binders for the wood board industry. The vegetable oil production in Europe is in its place offering the opportunity for a partial replacement of the actual binder system since sustainability elements indicate a better role as specialty ingredients rather than as commodity chemicals.

The project delivered novel technologies, both for enzymatic conversion of lipids and thermo/chemical conversion of carbohydrates which are scalable and applicable in industrial relevant environments.

Massimo Bregola of Cargill (on the right) presents SUSBIND at EFIB 2021 with Stephen Webb of RTDS (left)

Pilot scale evaluation of a new bio-based binder

Despite the COVID-19 restrictions and regulated access to laboratories and work environments, two Austrian SUSBIND partners, EGGER and Wood K Plus started a pilot scale evaluation of the new bio-based binder system in early 2021. This is one of the most important project milestones, opening the way for increased production capacities.

Sugar syrup as the secret ingredient

In the process of developing bio-based binders, SUSBIND tested several carbohydrate feedstocks like fructose, glucose, maltodextrin and found out that fructose-based adhesives have the fastest cure speed and that Fructose 5-Hydroxymethylfurfural improves the tensile shear strength of the adhesive system.

Production of adhesive precursors from carbohydrates via acidic dehydration and catalyst selection according to green chemistry principles that involved utilisation of 5-Hydroxymethylfurfural as adhesive crosslinker show promising results of the resin system is that is 85% bio-based. These precursors can be applied directly and the boards containing the SUSBIND adhesive fulfil the standard requirements for indoor furniture quality. The conversion of fructose to HMF was successfully implemented in a continuous microreactor as well as a pressurised batch reactor as shown in this compelling video.

Board hot-pressing and more to come

As a fine recap of the year, the research results were taken from the lab to the factory, the SUSBIND binder was applied to the wood chips in the hot press and the wood particle boards were pressed at the EGGER Group facilities in Austria, as illustrated in this demonstration video.

SUSBIND board pressing at EGGER Group (c) EGGER Group

Stay tuned for the next chapter as the SUSBIND journey will continue next year at our medium-density fibreboard (MDF) producer Valbopan in Portugal, and will then travel north to Sweden, to reach its final destination with our partner and global furniture producer IKEA.

Time ripe for synthetic biology, industrial biotechnology

Research and development in industrial biotechnology contributes to the growing European bioeconomy which according to the European Commission is worth around 614 billion euros and provides approximately 17.5 million jobs.

The leading industrial biotech event that represents this sector is the European Forum for Industrial Biotechnology and the Bioeconomy (EFIB) which opens in Vienna next week on Wednesday, 6 October until Thursday, 7 October.

The EFIB Forum will be held face-to-face which comes as a relief to many deprived of networking opportunities since the outbreak of the Corona virus pandemic in January 2020. Research , industry and SME from the Horizon 2020/BBI JU projects  SUSBIND and SUSFERT will be present at the event.

Both projects are hosted at the stand by communications partner RTDS. BBI JU Executive Director, Philippe Mengal, plans to visit the RTDS stand on Wednesday, where he will meet RTDS CEO, Stephen Webb, and project partners  project to discuss progress made, and challenges ahead in achieving a circular bioeconomy in Europe.

SUSBIND is a collaborative European research project in the field of bioeconomy that aims to replace conventional fossil-fuel binders currently used for wood-based panel boards in furniture with highly sustainable bio-based binders. By substituting fossil-based chemicals with those from renewable resources, carbon footprint of mass-produced furniture products will be reduced. A sustainable and economically viable binder will increase the marketability of bio-based furniture products.

Project partner Wood K plus, a leading research institute in the area wood and wood-related renewable resources developing the alternative bio-based adhesives based on carbohydrates together with EGGER have recently completed the pilot scale evaluation of a new bio-based binder system. “This is one of the most important project milestones, opening the way for increased production capacities” say Erik van Herwijnen, Team Leader “Advanced Bonding” at Wood K plus.

Scientific Coordinator, Massimo Bregola of Cargill is encouraged that this will lead to major breakthroughs. “The expertise brought together under the SUSBIND project will finally see development of a bio-based binder able to compete on an industrial scale. As we become increasingly demanding of green production methods in all areas, SUSBIND will provide Europe with a competitive advantage” he says.

Massimo Bregola- Global Technology Lead Coatings, Adhesives, Sealants & Elastomers – Cargill

Additionally, the SUSBIND partners will join BBI JU Executive Director, Philippe Mengal, and Sustainability and External Affairs Lead, Cargill Bioindustrial, Marty Muenzmaier, on the podium for EFIB’s final session OUTLOOK: The pathway to the future for industrial biotechnology. Both SUSBIND and SUSFERT are funded by the Biobased Industry Joint Undertaking (BBI-JU) under the European Union’s Horizon 2020 Programme.

SUSFERT is developing new biobased fertilisers to reduce dependency on unsustainable phosphorus imports into the EU. These fertilisers include novel controlled-release coatings from lignin as well as lignosulfonate-based soil improvers originating from wood pulp.  Waste sidestreams such as struvite is utilised to substitute imported phosphorus. The loss of nutrients from fertilisers in agriculture are being addressed by using probiotics to increase nutrient availability as the demand for food and feed rises.

Meet the SUSBIND and SUSFERT experts and discover the advances for the bioeconomy at Stand 5 during EFIB.

View the best moments from EFIB 2021 here.

A Word on Bioeconomy from Susanne Zibek of Fraunhofer IGB

In the “in demand” series, Fraunhofer IGB introduces the people behind the exhibits in the “Bioeconomy” and we are sharing an interview of one of our key scientists from the SUSBIND project.

We are conducting our eleventh interview with Dr.-Ing. Susanne Zibek from the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart. She conducts research on the cleansing properties of biosurfactants produced by fungi. You can find out more about this at the “Clean thanks to fungi” exhibit.

(C) Fraunhofer IGB: Susanne Zibek

How would you explain the term bioeconomy in simple terms?

In the future, we would like to use plants, biological residues and waste to make products for different industries. Examples are the areas for the production of plastics, detergents, cleaning and personal care products, paints, varnishes and coatings. First, the biological substances are separated and then converted by chemical reactions, enzymes or microorganisms. This is how you get bio-based molecules that can then be incorporated into consumer products.

What are you researching?

We develop processes with which new bio-based molecules can be produced from renewable raw materials. One example is the production of biosurfactants that can be used in detergents, cleaning agents and cosmetics. Biosurfactants have cleansing properties and can be produced by fungi in a bioreactor. The fungi are fed with sugar and vegetable oil. A biosurfactant is then naturally formed in the metabolism of the fungus and then discharged from the cell. The biosurfactant can then be purified and sent to companies to test its use.

Do you have an idea / wish where the results of your research could lead?

My vision is that we will soon have many shampoos, shower gels, creams, dishwashing detergents and detergents that contain our biosurfactant.

Which bioeconomic achievement would you like to see successfully implemented in everyday life by 2035?

I hope that the industry will produce more sustainable consumer products. It would be good to manufacture plastics, detergents and cleaning agents as well as textiles in a more environmentally friendly way and also to enable their recycling. I also wish that people would be more careful with their consumption.

What is the subject of your exhibit?

Our exhibit shows that we use plant-based substances such as sugar, straw or rapeseed to produce detergent substances. We use fungi for this, which naturally combine sugar and oil to produce biosurfactants. These can then be utilized in detergents.

What can visitors look forward to in your exhibit?

What does such a microorganism actually look like? At the exhibit, visitors can see microscopic images of Ustilago maydis. We called him Maydi. A comic illustrates how he makes the biosurfactants so that he has enough foam when bathing.

(c) Fraunhofer IGB: Ustilago-maydis-cellobioselipide2_Hellfeld

What do you find exciting about taking part in an exhibition like the one on the MS Wissenschaft?

It is important to us that we support the next generation and show how exciting research is and what can be done with plants and with biotechnology.

Was there anything that made you despair / think / laugh when you designed your exhibit? If yes, what?

Most people don’t know that there are so many microorganisms that we can use technically to make useful things. Perhaps many people are familiar with the production of alcohol with yeast in a fermentation reactor. Yeast is also a fungus. We proceed in a similar way: We also feed our fungi with sugar and oil, and we can produce a biosurfactant instead of alcohol. But there are numerous other microorganisms with which you can e.g. can produce lactic acid, acetic acid and many other bio-based molecules in the bioreactor.

If you are curious, you can take a first look at the exhibit here .

Original interview conducted by Fraunhofer IGB here.

Early-stage life cycle assessment in SUSBIND

The SUSBIND project aims to develop a new bio-based adhesive system for particleboard and medium density fibreboard (MDF) that achieves two main environmental goals:

  • a 5% lower carbon footprint;
  • lower human health impacts compared to the benchmark.

In a previous blog, CE Delft explained how progress towards these environmental goals is monitored and how life cycle assessment (LCA) is used to determine the carbon footprint of the new adhesive system. In this article, we would like to highlight why LCA is used at a very early stage of product development, and how this links to uncertainties and collaboration within the SUSBIND consortium.

Why apply life cycle assessment (LCA) early on in the development process?

By conducting an LCA early in a technological development process, environmental results can be used to make more informed, and ultimately better, decisions.

We know that a lot of choices need to be made when developing a completely new product. For example, for bio-based chemicals it may be possible to use different agricultural crops, there might be different chemical conversion processes to convert feedstocks into desired products, and different amounts of energy and auxiliary materials may be required. These choices all affect the final carbon footprint of the product as determined in an LCA (as well as other environmental performance indicators).

However, as development progresses from an initial idea towards lab-scale testing and pilot trials, it becomes increasingly difficult to switch to a different production route (or bio-based feedstock, or conversion process, or…). The choice to focus on one option therefore ‘closes the door’ on others. Applying LCA ensures that we understand the environmental consequences of these decisions, enabling the partners to stay as close to SUSBIND’s environmental goals as technically feasible.

By using LCA early on, we can show the environmental implications of different options so that they can explicitly be considered in the decision-making process. Environmental impacts can then be taken into account alongside other criteria, such as technical performance, feedstock availability, or costs.

Illustration of a technological development process. Over time, process data becomes increasingly certain as the process is developed and optimised. However, the room to make changes to the process decreases.

How are uncertainties in the analyses dealt with?

While we know that all carbon footprint studies typically have some degree of uncertainty, these uncertainties larger when conducting LCA early in a technological development process. For example, the chemical conversion route can still be changed, the types and amounts of reactants required still need to be fine-tuned, the energy balance is not yet optimised when working in a laboratory, etc.

In the environmental analyses for SUSBIND, CE Delft works with the best-available data at that time. If there are uncertainties or if assumptions need to be made, we clearly note these in the reports. In addition, the most important uncertainties/assumptions are studied in sensitivity analyses. For example, if we do not know how much energy a process requires, we can make an educated assumption. Subsequently, we can use sensitivity analyses to evaluate whether this uncertainty strongly affects a study’s conclusions. This approach can provide further guidance to the industrial partners by showing them which process parameters are critical and where it may be beneficial to gather improved data.

In our view, it is essential that we cooperate closely with the industrial partners in SUSBIND, since this ensures that we have a good understanding of the process, the data and their uncertainties.

What does the collaboration with the industrial partners in SUSBIND look like?

The industrial consortium partners work on various aspects of the technological development of new bio-based resins. Within CE Delft, we depend on their expertise and knowledge when conducting the carbon footprint analyses.

To start a new LCA, we typically prepare a detailed data questionnaire which is shared with one or several industrial partners (see the example below). This provides a good starting point for modelling the process and analysing its environmental impacts.

Click to enlarge: Example of a data questionnaire used for Deliverable 5.1

Click to enlarge: Example of a data questionnaire used for Deliverable 5.1

When we generate the first results of a new analysis, we often see that new questions arise. In addition, we may identify key parameters that drive the environmental performance of a studied product. Therefore, the results are extensively discussed among project partners to see whether the input data and modelling are correct and identify remaining issues (if any).

In the course of the overall SUSBIND process, we are continually refining our data sheets and values together with the industrial partners as the chemical production routes are optimised further and become more certain. This enables all of us to stay as close to SUSBIND’s environmental goals as technically feasible.

 

Author:

Martijn Broeren, senior consultant/researcher CE Delft

broeren@ce.nl

https://www.cedelft.eu/

SUSBIND in the Surface Coatings International Journal

Our project SUSBIND got featured in the Surface Coatings International (SCI)– Journal of the Oil and Colour Chemists’ Association.

We are sharing the original version here with you: “SUSBIND: Carbohydrate conversion to highly reactive intermediate chemicals for adhesives

Surface Coatings International Journal- May/June 2021

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sulfuric Acid-Catalyzed Dehydratization of Carbohydrates for the Production of Adhesive Precursors

SUSBIND develops the chemical syntheses for producing the carbohydrate-based amino-plastic, and other wood resin systems. This will polymerise urea and other monomers using intermediates derived from high-purified carbohydrates during WP1. This allows investigation of the reactions of the carbohydrates during resin synthesis and to test other modification reactions. This should deliver precursors suitable for using as bio-based binders for wood board production. Resins can be produced on laboratory scale to investigate properties and the most promising candidates are upscaled to pilot level to allow them to be validated as binders. Our Austrian partner WoodKPlus presents how this is done in its most recent publication. We share an extract below.

Switching to renewables

Today’s chemical industry still strongly relies on oil and other fossil resources as the main source of bulk chemicals and energy. Rising demands and diminishing fossil resources along with rising awareness of environmental problems drive the search for more sustainable alternatives. The interest in fuels and chemicals derived from renewables is therefore growing fast and a lot of R&D is done to convert biomass into valuable products. Biomass is the only widely available carbon source besides oil, gas and coal, and 75% of the available biomass are carbohydrates, such as starch, cellulose, or hemicelluloses.[1]

5-hydroxymethylfurfural (5-HMF) and its great industrial potential

The conversion of these carbohydrates into valuable chemicals, e.g., furanic compounds such as 5-hydroxymethylfurfural (5-HMF), has therefore huge industrial potential. 5-HMF is considered a key platform chemical since it can be converted into a variety of other valuable compounds. It has been called a “sleeping giant” along with furandicarboxylic acid (FDCA), a compound that can be derived directly from 5-HMF and may be a renewable alternative for terephthalic acid in polyester or polyamide production.[2]

Extensive literature on the production of 5-HMF is available, including good overviews of synthesis procedures, solvent systems, and proposed reaction mechanisms (Van Putten et al.[3]). Recently, we have added an outline of the challenging development of industrial 5-HMF production processes.[4]One of the main challenges in 5-HMF production is the formation of side products. In general, hexoses are dehydrated by acid catalysis to form 5-HMF. 5-HMF is easily rehydrated to levulinic and formic acid, on the one hand, and also polymerizes, on the other hand, thereby forming complex, black-colored residues called humins.

Figure 1. Conversion of fructose to 5-HMF and rehydration to the byproducts levulinic acid and formic acid via side reaction.

Abstract

Carbohydrates and hexose-derived 5-hydroxymethylfurfural (5-HMF) are platform chemicals for the synthesis of sustainable binders. New, greener approaches aim at the development of production systems, which minimize process steps and avoid organic solvents or other auxiliaries that could interfere with subsequent resin synthesis. In our work, carbohydrate solutions rich in 5-hydroxymethylfurfural (5-HMF) were produced using a continuous-flow microreactor and diluted H2SO4 as the catalyst. After optimization of the process conditions (temperature, reaction time, catalyst content), a 5-HMF yield of 49% was obtained at a low reaction time of 0.6 min and a catalyst concentration of 1% at 175 °C and 17 bar pressure. Extensive rehydration of the product was avoided by efficient immediate cooling of the reaction solution. The stability of the reaction system was improved by increasing the inner diameter of the capillary in the flow reactor to 2 mm. Advantageously, the obtained reaction mixtures are used directly as precursors in the development of sustainable binder systems, without the need of additional purification, filtration, or extraction steps. Read the full article here.

(c) Woodkplus

 

Authors of the publication:

Wilfried Sailer-Kronlachner, *Email: w.sailer-kronlachner@wood-kplus.at, w.sailer@boku.ac.at

Catherine Thoma, Stefan Böhmdorfer, Markus Bacher, Johannes Konnerth, Thomas Rosenau, Antje Potthast, Pia Solt, and Hendrikus W. G. van Herwijnen

Wood K plus—Competence Center of Wood Composites and Wood Chemistry, Kompetenzzentrum Holz GmbH, Altenberger Str. 69, A-4040 Linz, Austria

Institute of Wood Technology and Renewable Materials, Department of Material Science and Process Engineering University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz Str. 24, A-3430 Tulln, Austria

 

[1] Röper, H. Renewable Raw Materials in Europe–Industrial Utilisation of Starch and Sugar. Starch/Staerke 2002, 54, 89– 99,  DOI: 10.1002/1521-379x(200204)54:3/43.0.co;2-i [Crossref], [CAS], Google Scholar

[2] Sousa, A. F.; Vilela, C.; Fonseca, A. C.; Matos, M.; Freire, C. S. R.; Gruter, G.-J. M.; Coelho, J. F. J.; Silvestre, A. J. D. Biobased polyesters and other polymers from 2,5-furandicarboxylic acid: a tribute to furan excellency. Polym. Chem. 2015, 6, 5961– 5983,  DOI: 10.1039/C5PY00686D [Crossref], [CAS], Google Scholar

[3] van Putten, R.-J.; van der Waal, J. C.; de Jong, E.; Rasrendra, C. B.; Heeres, H. J.; de Vries, J. G. Hydroxymethylfurfural, Versatile Platform Chemical Made from Renewable Resources. Chem. Rev. 2013, 113, 1499– 1597,  DOI: 10.1021/cr300182k [ACS Full Text ACS Full Text], [CAS], Google Scholar

[4] Thoma, C.; Konnerth, J.; Sailer-Kronlachner, W.; Solt, P.; Rosenau, T.; van Herwijnen, H. W. G. Current Situation of the Challenging Scale-Up Development of Hydroxymethylfurfural Production. ChemSusChem 2020, 13, 3544– 3564,  DOI: 10.1002/cssc.202000581 [Crossref], [PubMed], [CAS], Google Scholar

JOIN US ON 8 JUNE 2021 FOR THE EU GREEN WEEK EVENT ONLINE TO DISCUSS HOW TO ACHIEVE ZERO POLLUTION OF AIR, SOIL AND WATER

The Market-driven Circular & Bioeconomy EU Green Week Partner Event brings together both science and industry of five European projects based on in the fields of low impact forestry & agriculture, low/no fossil chemistry and decarbonised transport. These include BIOVEXO Project – Biopesticides to fight Xylella, SUSFERT – SUStainable FERTtilisers, SUSTAINair – Sustainable aerospace value chains TECH4EFFECT – precision forestry and SUSBIND – SUStainable bio BINDers all of which are industry-driven circular and bioeconomy projects funded by the Bio-Based Industries Joint Undertaking (BBI-JU).

In line with the recently adopted action plan of the EC “Towards a Zero Pollution Ambition for air, water and soil – building a Healthier Planet for Healthier People”, the 2021 EU Green Week aims to showcase best practice projects, each contributing towards achieving zero pollution in their respective fields.

SUSBIND will be presented at the Green Week event by its Scientific-Coordinator of Cargill, Massimo Bregola who will discuss the importance of biobased binders and adhesives as well as green production methods and what they mean for the industry and the future of Europe. Our IKEA project partner representative, Johan Bruck, Material and Innovation Lead, will present lessons learned in SUSBIND in a panel discussion.

The registration for the event is free, however places are limited. Please REGISTER here!

Carbohydrate conversion to highly reactive intermediate chemicals for adhesives

In the SUSBIND project, 11 partners from science and industry are jointly researching bio-based binders for wood-based materials.

Wood K plus leads a work package on the development of a new technology for the production of carbohydrate-based binders. The selection of suitable chemicals as well as the successful implementation of a production process for a carbohydrate-based precursor was confirmed in the intermediate project evaluation in February 2020.

The conversion of fructose to the platform chemical 5-Hydroxymethylfurfural is a promising approach (Fig. 1) that was successfully implemented in a continuous microreactor as well as a pressurized batch (Fig. 2). The synthesis was designed in accordance with the principles of green chemistry, as such no hazardous solvents or catalysts were used.

Figure 1: Acidic dehydration of fructose to hydroxymethylfurfural

The reaction is based on the acidic dehydratization of a fructose solution using sulfuric acid as catalyst and water as solvent. The produced precursor solution, containing minor amounts of side-products, can be used directly in the adhesive production. This in-situ approach ensures that no additional purification steps are needed. The “waste stream” of the process is water that is separated in a concentration step. The project is continued with the development of adhesives for wood composites.

Figure 2: Carbohydrate conversion to highly reactive intermediate chemicals for adhesives

Promising enzymatic technology on the horizon & the up-scaling of the epoxidation of oil fatty acids for industrial applications

The oil from sunflower (Helianthus annuus) seeds is a promising raw material to obtain bio-based binder ingredients

As a collaborative European research & innovation project looking for the development as well as the scale-up of the production of SUStainable bio-BINDer systems for wood-based panels, SUSBIND is addressing the need for more sustainable bio-based binders used for wood-based panel boards in the European furniture industry.

Enzymatic reactions hold great potential to reshape the world, through the processing of agricultural and food industrial wastes, by creating sustainable by-products and favouring environmental rehabilitation. Therefore, the development of technologies for establishing successful enzyme-based processes has been very attractive in recent years to ensure sustainable and environmentally-friendly waste products.

Agricultural and food industry by-products and wastes can be utilized for manufacturing specialty and commodity chemicals, which may lead to the reduction in the dependency on fossil raw materials. Understanding the chemistry of these by-products and developing novel processing techniques has never been so important. This special issue is intended to attract cutting edge original research and recent advances on novel technologies applied to agriculture and food wastes as well as the processing of by-products.

Therefore, in their search for alternative binders produced from renewable resources, SUSBIND partners Instituto de Recursos Naturales y Agrobiología de Sevilla – IRNAS-CSIC (Seville, ES), Centro de Investigaciones Biológicas “Margarita Salas” – CIB-CSIC (Madrid, ES) and JenaBios GmbH (DE), together with Novozymes A/S (DK) recently shared their results in a scientific paper on promising enzymatic technology for epoxidizing complex mixtures of free or methylated fatty acids obtained from representative vegetable oils, under mild and environmentally-friendly conditions.

Enzyme technology broadly involves the production, isolation, purification and use of enzymes (in soluble or immobilized forms) for the ultimate benefit of humankind. In addition, recombinant DNA technology and protein engineering involved in the production of more efficient and useful enzymes are also a part of enzyme technology.

The article published by Frontiers in Bioengineering and Biotechnology, titled ‘High Epoxidation Yields of Vegetable Oil Hydrolyzates and Methyl Esters by Selected Fungal Peroxygenases’, takes into consideration economic aspects, technical suitability and sustainability, and concludes that an industry suitable solution for a bio-based binder ingredient could be based on sunflower oil. The sunflower oil is argued as the best solution for scaling-up the mild and selective production of epoxidized fatty acids using enzymes of the group of unspecific peroxygenases (UPOs), including both wild (e.g. MroUPO and CglUPO) and recombinant (e.g. rHinUPO) UPOs.

 

 

Rapeseed, soybean, sunflower or linseed oils are suitable raw materials for lipid compound production (including epoxide-type biobinders)

Rapeseed, soybean, sunflower or linseed oils are suitable raw materials for lipid compound production (including epoxide-type biobinders)A series of oil-producing plants of global significance are available for the production of renewable lipid epoxides and other oxygenated derivatives. Commercially exploited oil seeds, such as rapeseed, soybean, sunflower, or linseed, exhibited a considerable variation in their fatty acid profiles, which makes them suitable raw materials for the production of different lipid compounds. The hydrolyzated and transesterified products of the above-mentioned vegetable oils were treated with three fungal UPOs to obtain epoxides. The three enzymes were capable of transforming free fatty acids (FAs) and FA methyl esters (FAMEs) from the oils into the corresponding epoxide derivatives, although some significant differences in selectivity toward epoxidation were observed, with CglUPO being generally more selective. The results show that the fungal UPOs elude some of the limitations of other monooxygenases since they are secreted proteins, therefore far more stable, as they only require H2O2 for activation.

Moreover, their recent expression as soluble and active enzymes in Escherichia coli is expanding the number of UPO enzymes available from related genes in sequenced genomes and simultaneously. They enable the rational design of the available UPOs as ad hoc biocatalysts of industrial interest using protein engineering tools. Most noteworthy is the ability of these UPOs, particularly rHinUPO being able to produce triepoxides from these samples.

 

Unspecific peroxygenase (UPO) enzymes from fungi Marasmius rotula (MroUPO), Chaetomium globosum (CglUPO) and Humicola insolens (HinUPO), among others, are promising biocatalysts for the mild and selective epoxidation of unsaturated lipids

Unspecific peroxygenase (UPO) enzymes from fungi Marasmius rotula (MroUPO), Chaetomium globosum (CglUPO) and Humicola insolens (HinUPO), among others, are promising biocatalysts for the mild and selective epoxidation of unsaturated lipidsTherefore, UPOs appear as promising biocatalysts for the environmentally-friendly production of reactive fatty-acid epoxides given their self-sufficient monooxygenase activity with high epoxidation selectivity, including recently reported enantioselectivity (in addition to strict regioselectivity) of some of their reactions.

However, in spite of all recent progress in our understanding of UPO catalysis and application, some difficulties still remain to be solved, such as the inactivation by H2O2 which affects enzyme reuse.

This could be solved by the continuous feeding of low H2O2 concentration, or its in situ generation by enzymatic or chemical systems, thus further increasing the concentration of FA substrates and the final epoxide products.

 

Reference:

High Epoxidation Yields of Vegetable Oil Hydrolyzates and Methyl Esters by Selected Fungal Peroxygenases

Alejandro González-Benjumea, Gisela Marques, Owik M. Herold-Majumdar, Jan Kiebist, Katrin Scheibner, José C. del Río, Angel T. Martínez and Ana Gutiérrez

Front. Bioeng. Biotechnol., 05 January 2021, OPEN ACCESS, DOI: https://doi.org/10.3389/fbioe.2020.605854

Creating ad hoc enzymes for the production of the SUSBIND renewable bio-binders

Several thousand putative UPO (unspecific peroxygenases) sequences have been found in genetic databases and fungal genomes, indicating their widespread occurrence in the whole fungal kingdom, but only a handful of UPOs have been characterized so far, and almost nothing substantial is known on their natural function(s).

Their reliable heterologous expression remains tricky, despite all recent progress in this field.

Caption: Sections of wild peroxygenase (left) and a mutated variant (right) displaying the differences in their substrate access channels leading to the heme cofactor (red sticks). The engineered variant bears two phenylalanines (highlighted in aquamarine) that constrain the channel, switching the regioselectivity of the enzyme towards selective monoepoxide production from polyunsaturated fatty acids.

As a result of international collaboration within SUSBIND project, the CSIC-CIB-IRNAS (Spain), the Barcelona Supercomputing Center, the Technical University of Dresden (Germany) and the SME JenaBios (Germany) recently published in ACS Catalysis the development of novel fungal peroxygenases, which behave as “P450s with advantages”.

Both P450s and peroxygenases are enzymes that catalyse the oxygenation — the introduction of oxygen atoms — of a variety of substrates. Such reactions are very difficult to perform by chemical means, especially when the substrate is aliphatic, as is the case of fatty acids. Moreover, the use of enzymes is generally much more environmentally friendly than that of chemical catalysts. Enzymes are active under mild conditions, have a natural origin and are normally very selective in the catalysis, giving rise to fewer undesired by-products.

So, what is the meaning of peroxygenases which behave as “P450s with advantage”? Which is the advantage? Is the behaviour as a biocatalyst for oxygenation processes as a result of their self-sufficient monooxygenase activity? Yes, unspecific peroxygenases rely on H2O2 for catalysis, while P450s normally need other enzymatic partners and are less stable due to their intracellular nature. Furthermore, the study results give deeper insight into describing the structural basis for the catalytic properties on different fatty acids and, besides, show the potential to produce compounds of high-added value at preparative scale. As Municoy M. et al. have used powerful computational tools, such as the software PELE for ligand diffusion into proteins to simulate the behaviour of the enzymes on their substrates, being able to satisfactorily predict the oxygenation type (epoxidation versus hydroxylation) of the new peroxygenases. Computational data have been combined with the experimental analysis of the oxygenated products formed and process scale-up. Factors related to the enzymatic active-site architecture and the double-bond distribution in the different fatty acids were suggested by the computational analyses identified in experimental reactions and confirmed by site-directed mutagenesis of the heme access channel. In this way, the structural determinants for the catalytic properties of the different enzymes analysed have been unveiled.

The potential of this combined computational-experimental approach opens the door for new biotechnological processes for the enzymatic production of bio-based chemicals, which was further demonstrated by the preparative regio- and stereoselective epoxidation of α-linolenic acid. The product of this reaction, cis,cis-15(R),16(S)-octadeca-9,12-dienoic acid, was obtained by employing wild and engineered peroxygenases attaining 80−83% enantiomeric excess and over 99% regioselectivity. This, and other monoepoxides, from polyunsaturated fatty acids are nearly impossible to be obtained by other chemical means.

Therefore, their enzymatic synthesis developed as a final output of the study, represents a new and interesting reaction given the biological activity of these compounds, in addition to their application in organic chemistry as highly reactive molecules.

Confirming that epoxides of unsaturated fatty acids produced using the above-mentioned enzymes and vegetable oil feedstocks is a valuable finding within SUSBIND in its aim to develop a bio-based adhesive.

Reference: Fatty-acid oxygenation by fungal peroxygenases: From computational simulations to preparative regio- and stereoselective epoxidation. Municoy M., González-Benjumea A., Carro J., Aranda C., Linde D., Renau-Mínguez C., Ullrich R., Hofrichter M., Guallar V., Gutiérrez A., and Martínez A.T. 2020. ACS Catal.  http://dx.doi.org/10.1021/acscatal.0c03165