Periodic Reporting for period 2 - WoodZymes (Extremozymes for wood based building blocks: From pulp mill to board and insulation products)
Okres sprawozdawczy: 2019-12-01 do 2021-11-30
Among the three main components of wood, paper industry mainly exploits cellulose, which implicates the removal and loss of lignin and hemicelluloses in the mill side-streams. However, these fractions are valuable renewable sources of aromatic compounds and sugars that can be valorised into new bio-based products. Thus, a main challenge faced by paper pulp industry is to attain the full exploitation of wood components.
WoodZymes project aims to provide biotech solutions to address this challenge through the development of extremophilic enzymes (extremozymes) able to work under the extreme operation conditions of high temperature and alkalinity demanded by kraft pulp and fibreboard industries. The goal was to valorise the underutilized lignin and hemicelluloses from kraft pulp mills into bio-based building blocks to replace fossil-derived chemicals in selected applications, through the extremozyme-assisted depolymerization of lignins and delignification and bleaching of pulps.
The WoodZymes consortium covers the whole value chain, from feedstock suppliers to end-users, being able to demonstrate the extremozyme-based technologies at pilot scale: i) world-leading companies of the pulp & paper (The Navigator Company and Fibre Excellence), fibreboard (FINSA) and insulation material (Soprema) sectors; a biotech SME commercializing industrial enzymes (MetGen); and reputed research institutes (CSIC: CIB, IATA and IRNAS) and technological centres (CTP, FCBA and RAIZ) of the wood, cellulose, lignin and enzyme sectors.
WoodZymes project aims to provide biotech solutions to address this challenge through the development of extremophilic enzymes (extremozymes) able to work under the extreme operation conditions of high temperature and alkalinity demanded by kraft pulp and fibreboard industries. The goal was to valorise the underutilized lignin and hemicelluloses from kraft pulp mills into bio-based building blocks to replace fossil-derived chemicals in selected applications, through the extremozyme-assisted depolymerization of lignins and delignification and bleaching of pulps.
The WoodZymes consortium covers the whole value chain, from feedstock suppliers to end-users, being able to demonstrate the extremozyme-based technologies at pilot scale: i) world-leading companies of the pulp & paper (The Navigator Company and Fibre Excellence), fibreboard (FINSA) and insulation material (Soprema) sectors; a biotech SME commercializing industrial enzymes (MetGen); and reputed research institutes (CSIC: CIB, IATA and IRNAS) and technological centres (CTP, FCBA and RAIZ) of the wood, cellulose, lignin and enzyme sectors.
A set of new thermophilic and alkaliphilic enzyme, xylanases acting on hemicelluloses and laccases acting on lignin, were discovered by in silico screening of databases or developed by protein engineering. Two patent applications were filed, covering a new xylanase with outstanding extremophilic properties and The best performing enzymes reached pilot or industrial scale production.
Kraft lignins isolated from the black liquors of the consortium pulp mills were enzymatically fractionated with METNINTM lignin refining technology, which combines the depolymerisation of lignin by laccase at alkaline conditions with a cascading membrane operation. Sets of softwood and hardwood kraft lignin-derived fractions with decreasing size and increasing phenol content were produced and chemically characterized.
The lignin fractions were oxypropylated to obtain liquid polyols to be used in the formulations of rigid PU foams, attaining up to 50% substitution of fossil-derived polyols. All the lignin samples were compliant with foaming requirements although some process adaptations are required for industrial implementation depending on the lignin properties.
The new extremophilic laccases and lignin fractions were also tested in the manufacture of Medium-Density Fiberboards (MDF). The extremozymes had a positive effect on energy savings during defibring of wood chips. Lignin fractions were applied as a phenol substituent in the formulation of lignin-phenol-formaldehyde (LPF) resins aiming to reduce the content of fossil-derived chemicals. A deep chemical characterization of the resins provided valuable knowledge of the resin formation process. It was possible to obtain suitable resin formulations with a substantial decrease of phenol and formaldehyde contents to values never obtained in these applications.
In the case of kraft pulp delignification and bleaching, the integration of the new extremozymes (laccases or xylanases) in the bleaching sequence allowed reducing the chlorine dioxide load. In particular, bleaching of eucalyptus kraft pulp at pilot scale with the most extremophilic xylanase enabled to save 25% chlorine dioxide, at higher brightness than that currently obtained at the mill, with concomitant 18% reduction of the organochlorinated compounds released in the effluents, and without affecting pulp mechanical properties.
Highly pure hemicelluloses were extracted from bleached kraft pulps with the aid of extremophilic xylanases. These sugars were chemically modified and evaluated as additives in papermaking, allowing up to 80% energy savings during paper refining and notably improving the mechanical and physical properties of paper sheets when added as paper binders. The paper sheets can be recycled preserving the enhanced properties.
The techno-economic and environmental impact assessment showed that the extremozyme-assisted processes lead to clear energy savings during refining of pulp and wood fibres and chemical savings in pulp bleaching, thus reducing their environmental impact. Besides, it showed the increased sustainability of the new products, with a lower carbon footprint (e.g. 60% reduction in LPF resins), due to the replacement of petroleum-based components by bio-based ones.
Two patent applications covering new extremozymes have been filed, and a third one related to the new LPF resins is under evaluation. Other results will be directly exploited by partners, through new research contracts or have been published in high impact journals enabling direct knowledge transfer. A Final Workshop was organized to present the main WoodZymes achievements, which are also illustrated in an animated video available at the website.
Kraft lignins isolated from the black liquors of the consortium pulp mills were enzymatically fractionated with METNINTM lignin refining technology, which combines the depolymerisation of lignin by laccase at alkaline conditions with a cascading membrane operation. Sets of softwood and hardwood kraft lignin-derived fractions with decreasing size and increasing phenol content were produced and chemically characterized.
The lignin fractions were oxypropylated to obtain liquid polyols to be used in the formulations of rigid PU foams, attaining up to 50% substitution of fossil-derived polyols. All the lignin samples were compliant with foaming requirements although some process adaptations are required for industrial implementation depending on the lignin properties.
The new extremophilic laccases and lignin fractions were also tested in the manufacture of Medium-Density Fiberboards (MDF). The extremozymes had a positive effect on energy savings during defibring of wood chips. Lignin fractions were applied as a phenol substituent in the formulation of lignin-phenol-formaldehyde (LPF) resins aiming to reduce the content of fossil-derived chemicals. A deep chemical characterization of the resins provided valuable knowledge of the resin formation process. It was possible to obtain suitable resin formulations with a substantial decrease of phenol and formaldehyde contents to values never obtained in these applications.
In the case of kraft pulp delignification and bleaching, the integration of the new extremozymes (laccases or xylanases) in the bleaching sequence allowed reducing the chlorine dioxide load. In particular, bleaching of eucalyptus kraft pulp at pilot scale with the most extremophilic xylanase enabled to save 25% chlorine dioxide, at higher brightness than that currently obtained at the mill, with concomitant 18% reduction of the organochlorinated compounds released in the effluents, and without affecting pulp mechanical properties.
Highly pure hemicelluloses were extracted from bleached kraft pulps with the aid of extremophilic xylanases. These sugars were chemically modified and evaluated as additives in papermaking, allowing up to 80% energy savings during paper refining and notably improving the mechanical and physical properties of paper sheets when added as paper binders. The paper sheets can be recycled preserving the enhanced properties.
The techno-economic and environmental impact assessment showed that the extremozyme-assisted processes lead to clear energy savings during refining of pulp and wood fibres and chemical savings in pulp bleaching, thus reducing their environmental impact. Besides, it showed the increased sustainability of the new products, with a lower carbon footprint (e.g. 60% reduction in LPF resins), due to the replacement of petroleum-based components by bio-based ones.
Two patent applications covering new extremozymes have been filed, and a third one related to the new LPF resins is under evaluation. Other results will be directly exploited by partners, through new research contracts or have been published in high impact journals enabling direct knowledge transfer. A Final Workshop was organized to present the main WoodZymes achievements, which are also illustrated in an animated video available at the website.
Enzymatic biocatalysts are expected to support the development of new processes and products in the wood conversion sector. Considering the extreme conditions of current industrial processes for pulp and fibreboard production, the new extremozymes developed here constitute a step forward towards turning kraft pulp mills into wood biorefineries.
Kraft lignins account for about 85% of global lignin production, but there is no established catalytic technology for their high-value exploitation, which implicates their breakdown into aromatic chemicals and building blocks. In WoodZymes we addressed this problem by the enzymatic fractionation of kraft lignins with tailor-made extremophilic laccases. We also demonstrated the feasible enzyme-aided extraction and use of pulp hemicelluloses as additives in papermaking.
The new extremozymes and extremozyme-aided technologies enable the valorisation of residual biomass streams of kraft pulp mills into bio-equivalents of fossil-based components in several products, while open new scenarios for the industrial processes. On one hand, WoodZymes approach assists to overcome kraft mills’ bottleneck (i.e. the limited capacity of the recovery boiler) through the integrated production of lignin from black liquors in the mill. On the other hand, it enables smooth incorporation of biomass subproducts into the production process (e.g. use of hemicelluloses as pulp refining aids and paper binders), closing the loop of the kraft process.
WoodZymes facilitates new interconnections between different industrial sectors, which can lead to increase the competitiveness of EU kraft pulp biorefineries by the exploitation of all components of the biomass feedstock in various applications beyond those tested in the project.
The adoption of clean and environmentally sound technologies based on extremozymes leads to energy and chemical savings in the industrial processes. Moreover, the sustainability of the WoodZymes products is increased by turning from fossil to bio-based components, reducing the dependence on fossil resources with cost benefits (e.g. through the use of competitive renewable lignin) and less environmental impact (e.g. reduced carbon footprint), as shown by life-cycle assessment.
Kraft lignins account for about 85% of global lignin production, but there is no established catalytic technology for their high-value exploitation, which implicates their breakdown into aromatic chemicals and building blocks. In WoodZymes we addressed this problem by the enzymatic fractionation of kraft lignins with tailor-made extremophilic laccases. We also demonstrated the feasible enzyme-aided extraction and use of pulp hemicelluloses as additives in papermaking.
The new extremozymes and extremozyme-aided technologies enable the valorisation of residual biomass streams of kraft pulp mills into bio-equivalents of fossil-based components in several products, while open new scenarios for the industrial processes. On one hand, WoodZymes approach assists to overcome kraft mills’ bottleneck (i.e. the limited capacity of the recovery boiler) through the integrated production of lignin from black liquors in the mill. On the other hand, it enables smooth incorporation of biomass subproducts into the production process (e.g. use of hemicelluloses as pulp refining aids and paper binders), closing the loop of the kraft process.
WoodZymes facilitates new interconnections between different industrial sectors, which can lead to increase the competitiveness of EU kraft pulp biorefineries by the exploitation of all components of the biomass feedstock in various applications beyond those tested in the project.
The adoption of clean and environmentally sound technologies based on extremozymes leads to energy and chemical savings in the industrial processes. Moreover, the sustainability of the WoodZymes products is increased by turning from fossil to bio-based components, reducing the dependence on fossil resources with cost benefits (e.g. through the use of competitive renewable lignin) and less environmental impact (e.g. reduced carbon footprint), as shown by life-cycle assessment.