The accumulation of wood extractives in paper mills, forming 'pitch deposits', results in low-quality pulp and blockages causing important economic losses as well as effluent toxicity. This proposal focuses on the pilot-scale development of environmentally sound methods for pitch control during the manufacture of selected pulps (spruce TMP and eucalypt TCF-bleached kraft pulp).
The objective of this project is to design environmentally sound methods for pitch control during the manufacture of selected paper pulps based on:
1) the previous balance of extractive-derived compounds during the manufacturing of eucalypt kraft pulp and spruce TMP pulp, and the identification of compounds responsible for pitch deposition
2) selected fungal strains to remove extractives from both wood types
3) new (native or engineered) enzymes, able to degrade target compounds in pulps or liquids
4) improved physicochemical methods to remove pitch or decrease deposition.
To develop the above pitch control methods at a pilot scale, the objectives include:
1) fungal growth optimisation and formulation of inocula to treat wood
2) optimised protocols for the production of the new enzymes developed
3) combined enzymatic-physicochemical treatments
4) pilot-scale pulping and bleaching, including the above optimised treatments
5) analysis of the advantages of the new processes in terms of extractive removal, pitch deposition, pulp and process parameters, and effluent toxicity
6) evaluation of their commercial interest for different raw materials, pulping processes and world markets.
Progress to Date
Two of the eight project work packages were already completed at the beginning of the third project year. The other six work packages were in progress during the present reporting period and the European Union approved a six- month extension of the project duration. In addition to the five project milestones already attained during the first (milestone 2) and second years (milestones 1 and 3 to 5) of the project, two more milestones were attained during the third year. Finally, the four milestones of Work Packages 7 and 8, initially scheduled for the end of the third year, have been postponed to the end of the six-month extension. Work to attain these milestones is already underway.
The results obtained show that the project is progressing satisfactorily. An important part of the work performed during the third year focused on the scaling-up of biological treatments for pitch control. The aim of these studies, which were initiated in the present year, was the use of fungi as chip inocula and enzymes as pulp additives. However, other studies initiated in previous years were also continued during the third year. These include:
1) the laboratory-scale study of other advantages of the fungal treatment of wood, in addition to their positive effect on removing extractives already shown in previous reports
2) the final screening of the most promising resinase variants obtained by protein engineering, and the characterisation and production of new wild enzymes (sterol esterases)
3) the evaluation of physicochemical methods for pitch control (alone and in combination with some of the new enzymes developed in the project).
Other aspects of the project work, such as the chemical characterisation of extractives and deposits, and the selection of the best fungi to be used in inocula for biological control of pitch, were concluded during the second year.
FORESTRY, NON-FOOD PRODUCTS
Scientist responsible for the project
Professor ANGEL T. MARTINEZ
Spain - ES
Phone: +34 9156 11800
Fax: +34 9156 27518
||Centro de Investigaciones Biológicas (CIB) - Consejo Superior de Investigaciones Científicas (CSIC)
||01 January 2000
||3 133 224 €
|Total EC contribution
||1 477 759 €
|Web address of the project
- ENCE - Centro de Investigación y Tecnología (CIT), Spain - ES