BioMatNet Item: AIR2-CT93-1219 - Biological Delignification in Paper Manufacture: Optimisation of Enzyme Mixtures for Treating Cereal Straw and Other Non-Woody Materials

AIR2-CT93-1219
Biological Delignification in Paper Manufacture: Optimisation of Enzyme Mixtures for Treating Cereal Straw and Other Non-Woody Materials

Contacts
Website: www.cib.csic.es/~lignina/straw_en.html
Further Information

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AIR Cluster VII - Forestry and Forest Products : Biological Conversion : Biotechnology : Paper/Pulp : Pulping : Straw

	Contract No	AIR1-CT92-0041
	Total Cost	4 143 789
	EC Contribution	2 500 000
	Start Date	01/01/1993
	Duration	33 months

SUMMARY

This project has investigated in detail the use of various biological treatments, based on either growing fungi or isolated enzymes, in the preparation of paper pulp from straw. Straw, in common with other fibrous lignocellulosic materials, is made up of the cellulose components which form the bulk of the final paper, as well as hemicellulose (carbohydrate) and lignin (phenolic) materials which are removed and/or bleached during processing. Conventionally pulping uses alkali salts and may use strong chemical bleaches based on chlorine, which produces polluting effluents and environmental concern. The enzyme approach should provide less degraded by-product streams and reduced environmental impact. However, although many fungi produce enzymes which breakdown hemicellulose and some produce lignin degrading systems, considerable development and optimisation is required to make such approaches commercially viable. As indicated here, this groups has made significant advances in understanding of the mechanisms and possibilities.

OBJECTIVE

The objective of the project is to optimize enzymatic treatments for straw delignification - through an interdisciplinary approach that will take into account gramineous peculiarities both in tissue anatomy and chemical structure of cell wall polymers - in order to provide a biotechnological solution (increasing paper productivity by improved dewatering, and decreasing lignin in effluents) to some of the main drawbacks of straw for pulp production, and to reduce simultaneously the costs of energy and chemicals used in pulp manufacture that will be combined with biological means. The above interdisciplinary approach will include the following tasks:

Testing and improving strains of selected species of ligninolytic fungi for preferential degradation of straw lignin
Identification and production of the fungal enzymes that could contribute to lignin removal, including those acting on phenolic and non-phenolic lignin moieties, and those splitting linkages with other straw polymers
Enzymatic treatment of straw by the individual enzymes and by enzyme mixtures, which will exhibit synergistic effects (e.g., ligninolytic enzymes assisted by enzymes providing co-substrates or preventing repolymerization of degradation products)
Evaluation of the efficiency of the above enzymatic treatments in terms of the modifications of lignin composition and its relationships with other cell-wall polymers
Monitoring histological changes produced by enzymes in order to verify the degradation of undesirable tissues (e.g., Parenchymatic cells included in the fine fraction of pulp) and the preservation of fibre structure
Testing pulping properties of the enzyme-treated straw, compared with fungus-treated straw and semichemical pulp, in combination with other pulping treatments and with special emphasis on the reductions in energy and chemicals and the decrease in the amount of lignin-derived products in effluents.

Contacts

Coordinator

Angel T MARTINEZ / CIB, CSIC Centro de Investigaciones Biológicas Consejo Superior de Investigaciones Científicas / SPAIN

EC Scientific Officer

Ciarán MANGAN / European Commission - DG Research Quality of Life Programme - Unit B1.2 / BELGIUM

Participant