Bioplastics made from plants

Bioplastics produced from genetically modified plants could help reduce the burden placed on the environment by conventional plastics. Much in the same way as animals use fat as an energy store, certain bacteria use substances similar to plastics. These can be isolated and processed into bioplastic. In contrast to plastics conventionally manufactured from mineral oil, bioplastics are produced from renewable resources such as vegetable fats, oils, or carbohydrates. They are completely biodegradable and can be used as a source of nutrients by a lot of naturally occuring microorganisms.

Photo: green-water.org

Bioplastic is still relatively expensive however, since the yield is very small. Genetically modified bacteria or plants may in future be used for industrial-scale production. Bioplastics could contribute in medicine; particularly in surgery where body-compatible implants are called for, or in the packaging-materials industry. The use of compostible shampoo bottles, beverage cartons, baby diapers, and other packaging materials could constitute an enormous reduction in the environmental burden imposed by conventional plastics.

Since May 1997, the British Cooperative Bank has been offering credit cards made of biodegradable plastic. The cards consist of “Biopol”, a bioplastic manufactured by Monsanto using microorganisms. Biopol is obtained from renewable resources (e.g. sugar or vegetable fatty acids) and can be disposed of by composting, being 99.9% free of the ecologically problematic plastic PVC.

Employing genetic-modification methods Monsanto has also developed plants (oilseed rape) that produce relatively small amounts of Biopol (5% of the total weight) in their cells. The ultimate aim is to develop plants that consist of up to 20% by weight of Biopol, thereby enabling various bioplastics to be produced for a wide variety of applications.

Plants that degrade and are resistant towards deleterious substances

Genetic modification not only offers assistance in avoiding environmental damage - it can also be applied to relieve ecological damage that has already occurred, by using microorganisms or plants that degrade various pollutants.

The methods traditionally used to eliminate industrial pollution are limited: contaminated soils for example, are excavated and deposited at waste dumps or else incinerated in special facilities. In both cases the transport costs involved are high, and the humus - which is important for the fertility of the soil - is lost in the process. When the soils are deposited, the pollutants are not destroyed, they are merely removed from the public eye, and the threat is merely postponed. In built-up areas, it is often impossible or at least extremely difficult to remove contaminated materials.

Bio-remediation constitutes an efficient, ecologically compatible, and inexpensive alternative to traditional techniques. Ideally, these methods enable the pollutants to be degraded into inorganic compounds in situ in the soil or groundwater using naturally occurring microorganisms.

Aluminium-tolerant plants: Many soils worldwide are contaminated with aluminium, with the result that harvest yields are severely reduced. A Mexican research team has transferred the gene for an enzyme responsible for the development of citric acid to various plants, such as, papaya and tobacco. Compared with normal plants, these exhibit significantly better growth in aluminium-contaminated soils. While this should not detract from the importance of avoiding contamination of soils with aluminium in the first place, plants such as these could one day play a decisive role in solving problems where such contamination has already occurred.

In another development, American scientists at the University of Georgia have succeeded in cultivating mustard plants that have the ability to take up mercury and convert it into a chemical compound that is far less damaging to the environment. If the results of the laboratory experiments translate into practice, in future it might be possible to clean up mercury-contaminated soils by the cultivation of such plants instead of having to deposit these soils in special waste dumps.

source: uropabio.org