New Techniques for Extractives Isolation

The major problem seems to be that much of the polyphenolic polymers in the bark are primarily insoluble in simple neutral solvents such as water or alcohol under non-pressurized conditions. When they are extracted with dilute alkali, they are strongly subject to chain degradation, oxidation to quinones, ring-open- 

Some of the advantages that can be visualized for a process of this type are a large, low-cost source of clean terpenes and resin acids improved uniformity of kraft cooking that would not be inhibited by the presence of resinous constituents no fatty or resin acid soaps that create foaming on brown stock washers and require additions of defoamers for control and, most importantly of all, no toxic fatty or resin acids in the bio-basin effluent discharge. The inherently more expensive northern wood resource, compared to subtropic plantation eucalyptus or other hardwoods, would be enhanced by the co-production of products, which would help to provide a competitive balance. 

There are some potential disadvantages to such a utilization scheme Are there markets that could absorb a very large increase in availability of resin acids and terpenes New end-uses would certainly need to be developed. Another major unanswered question has to do with fats. Would they also be produced in the auxin pretreatment process Will they be present in the wood as free fatty acids or as glycerides If the latter, what will be their effect on processing These are the types of questions that need to be answered in an industrially-oriented program that combines increased resin and terpene generation with new isolation schemes. 

A technique that initially held promise for replacing whole plants, or parts of plants, for production of useful secondary metabolites is plant cell culture. After about ten years of intensive industrially-supported effort, many technical prob- 

One of the problems is that compounds are not accumulated in cells but are released into the culture medium where they are lost, if volatile, or may interfere biologically with subsequent cell growth and division. This problem has been dealt within cell cultures of Thuja occidentalis (eastern white cedar) by Berlin and co-workers (4) by adding an insoluble solvent trap to collect terpenes and tropo-lones released into the medium. The yield of thujaplicins was nearly tripled over the duration of the fermentation by this technique. Nevertheless, the secondary metabolite generated by the Thuja cultures did not replicate what might be expected from any specific part of the tree. 

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