| Energy | Biomass | Genetics | Micro-organisms | Phyto-chemistry | Bio-synthesis | Separation technologies | Biorefinery |

Separation technologies

On the occasion of the first annual ZERI-meeting meeting the Biofocus Foundation was pleased to receive a bery substantial donation from Volvo/Swedish Match. It had the form of a 20 ton/day steam explosion pilot plant located in the US. The donor had no use for this facility after the holding company concerned (Procordia) had made a decision to concentrate its research resources on core activities. which did not involve phyto-chemistry. When ecological economists consider the input/output of future ZERI:s, they should obviously supplement their energy-and life-cycle analysis with studies of the potential of various materials for a step-wise multi-purpose use.

It is against this background that the biorefinery concept pro-videsfood for thought about a future chemical industry which might be characterized by a wide range of products that are more or less directly derived from photosynthesis. Since their rawmaterial base is dispersed as well as site-specific, depending on the available water and nutrients, the technologies that would be needed for their up-grading ought to be adaptable, small-scale and in some cases also mobile, Otherwise the waste of energy, and the emissions generated by long distance transports, cannot be substantially reduced. For develop-ing countries such technologies would also have the advantages of:

1. being compatible with local energy sources (biofuels, solar stills and dryers, wind power, small water tubine generatorsetc.),
2. requiring a modest capital inputs,
3. providing sites for on-the-job training,
4. increasing local self-reliance, and
5. counteracting rural poverty.

In this connection the potential of plant biotechnology is obvious, but it should also be mentioned that, just as plant geneticists can now make tomatoes that tolerate long transports, they can also select and design plants that are particularly well suitable for local upgrading .

Suppose for instance that one decides to use wood as a chemical feedstock. To reduce the input energy a nitrogen-fixing and rapidly growing tree suitable for harvesting from shoots would then be selected, preferably a sterile hardwood, since this would not spread into the wild type environment, would give about 20 % higher yield and could be patented. If it could also be used as a "living fence" for ani-mals that could feed on its canopy, that would of course provide an added advantage to a nearby "Biovillage".

However, to underline the aim of reducing emissions by means of comprehensive use, wood should also be considered as a con-struction material. After its useful life had come to an end it might† then be chipped to serve as fuel, or as a chemical feedstock for a nearby "Biorefinery".

In the latter case, the question is then which technology that should be used for partitioning the wood without eroding the intrinsic value of its three major components: lignin, hemi�cellulose and cellulose. After all, some of those components might find local uses (for instance as a moulding compound or as lignin adhesives in building materials), whereas others could be sold to specialized distant factories.

In such large and well-equipped facilities the hemicellulose might then for instance be used as the substrate for an alcohol fermen-tation or for the production of xylitol, and the micro�crystalline cellu-lose might be upgraded to an environmentally sound "dissolving cellulose". From the experience gained before the boom in† petrochemistry started, we know that such a material could have very wide technical applications (rayon, cellophane, parchment paper, cellulose plastics etc.).

The following summary of applications might give some idea about the challenging problem which is faced by anyone who wants to design industrial clusters based on the major components of ligno-cellulose (italics† indicate areas which ought to be of special significance to developing countries):

The Lignin is often burned as a heatsource, but it can also serve as a key ingredient of dispersants which can not only be used in dyes and inks, but also forconverting coaldust into a liquid fuel. Another energy-related use is for ligninbased surfactants to support enhanced oil recovery. Lignin has also been used as a replacement for carbon black in tires, as a binder in asphalt and† as an adhesive in plywood and particle boards.. As a thermoplastic resin, lignins have been used in the production of coatings and foams, and they have also served as encapsulating agents for slow-release fertilizers, insecticides, and plant hormones. They have the ability to protect labile materials and vitamins, when these are incorporated in products such as fish-fodder. They absorb bile acids in rumen fluids. and they can be fragmented to yield chemicals like vanillin, phenol, cresols and cathecols.

Cellulose fibers have an established position in paper�making and have also been used in composites based on concrete† or various polymers. They can however also serve as animal fodder and as substrate for microorganisms and mushrooms.† Microcrystalline cellulose improves the printing quality of paper, but it is also suitable for chemical grafting, ranging from simple nitrification to produce explosives, to the addition of groups that greatly in-crease or decrease the water holding capacity. In the food-and pharmaceutical industries microcrystalline cellulose can also find use as a low-calorie addition in bread, as gels that resist freezing, as a tablet base or as a carrier of flavor substances, aromatic oils and enzymes. Finally, cellulose can of course be hydrolyzed to yield glucose which can then be fermented to acids, alcohols, polyols and ketones.

Hemicellulose, low in microbial inhibitors, can be hydrolysed and then used as a substrate for producing protein fodder† or ethanol. The xylose sugar produced by hydrolysis can also be hydrogenated to xylitol or dehydrated to furfural. The latter can then open up a vaste field of applications (Fig.3) ranging from rubber (Divinyl-ethylene), paints-and varnishes (solvents and diluents), nylon and other polymers, selective solvents for vegetable oils and fatty acids, as well as many products of organic synthesis in-cluding raw material for many drugs, perfumes and agricultural chemicals such as herbicides, fungicides, insecticides, bacteriocides and disinfectants.