Genetic engineering in wood for the paper and boar
The paper and board industry is placing greater demands on the existing plantations and forests producing wood pulp because of the rapid growth in paper products. In the UK only 10% of land is forested; this has ment that the uk is dependant on timber imports. Biotechnology is being used to experiment on genetically modified (GM) trees for producing higher yeilds of wood pulp. GM occur by artificially inserting genes from 1 plant to another, producing changes in the trees biological characteristics.
- GM trees are quicker growing and provide a sustainable supply of wood pulp
- GM trees are resistant to disease and insect attack so they provide high quality products
- reduced lignin in trees enabling a reduction in the amount of chemicals needed in the paper making process
- better forest management which reduces the amount of deforestation
- paper is treated to biodegrade quicker and more easily, it is produced more efficiently and faster
- escape of modified genes into the natural ecosystems, insect and disease become resistant to modified trait
- Rapid growth could cause shorter, more intensive rotations resulting in greater water demand and reduced opportunity for nutrient recycling
Biodegradable polymers are materials derived from renewable raw materials that will decompose in the natural environment. Biodegradation occurs when micro-organisms in the environment breakdown the molecular structure of the polymer to produce a material that is inert and less harmful to the environment. Some biodegradable polymers are fully degradable as they are purely from renewable sources, others are semi degradable, mixing renewable sources with existing petroleum derived synthetic polymers.
- fully degradable in suitable conditions
- reduction of time in landfill and the associated harmful effects
- starch-based plastics are formed from carbon that is already in the ecosystem so does not contribute to global warming
- degradation of some plastics still contributes to global warming through the release of CO2
- damages recycled plastics when mixed and reduces their value
- fully biodegradable polymers are expensive as they are not widely produced
- may not be as energy efficient to produce synthetic polymers e.g. polypropylene
- semi-biodegradable polymers remain in the environment for years
- Biopol is a trade name of the British chemical company ICI for the first fully biodegradable polymer, polyhydroxylbutrate (PHB), developed commercially in the early 1990s. The first use for biopol was in the packaging industry to produce blow moulded shampoo bottles as the material was water resistant and provides an effective barrier to air.
- Biopol is made in nature via fermentation, by Alcaligenes eutrophus bacteria, of sugars and other carbohydrates that are collected in their cellsas reserve material. Once the reserve material is seperated and refined from the bacteria, a white polymer powder is extracted. this polymer can be used in the usual manufacturing processes to produce plastic products. The advantage of biopol is that it is produced naturally by renewable sources, and it is fully biodegradable.
- Biopol is stable when stored in air and in humid conditions. Degradation to CO2 and H2O will only occur if the polymer is exposed to microorganisms found naturally in soil, sewage, river bottoms, and other similar environments. The rate of degradation depends on the material thickness and the number of bacteria present. Biopol degrades more rapidly without oxygen present which is significant because oxygen is not present in modern sealed lanfills.
the eco-bottle is made from PLA (polylactic acid) which is derived from corn starch. The use of PLA over PET and HDPE bottles has certain advantages:
- Regular plastic bottles use finite resources (e.g. oil & gas) whereas corn is a renewable source
- PLA is made using a totally carbon-neutral process. ( no greenhouse gases emitted).
- PLA is biodegradable, so it breaks down safely and quickly
Innocent is encouraging its customers to compost these bottles with all of their green waste. The eco-bottle can be recycled along with regular plastic bottles in the normal way but, to maintain the quality of the recycled material, compostable bottles should not make up more than 1% of the mix.
The disadvantages are that there is a lack of composting infrastructure around. only 10% of the UK's recycling centres have machines that can sort these bottles from the normal PET and HDPE plastic bottles. Therefore the company has to be careful about how many compostable bottles it releases into the market before the correct facilities are in place to handle them.