Bioplastics

Introduction:

• Bioplastics or organic plastics are a form of plastics derived from renewable biomass sources, such as vegetable oil, corn starch, pea starch or micro biota. Plants are also  becoming factories for the production of plastics. Researchers created a Arabidopis thaliana plant through genetic engineering. The plant contains the enzymes used by bacteria to create plastics. Bacteria create the plastic through the conversion of sunlight into energy. The researchers have transferred the gene that codes for this enzyme into the plant; as a result the plant produces plastic through its cellular processes. The plant is harvested and the plastic is extracted from it using a solvent. The liquid resulting from this process is distilled to separate the solvent from the plastic. 

Global producers:

US, Europe and Asia pacific are the top producers of bioplastics in the world.

Process:

Bioplastics are made from a compound called polyhydroxyalkanoate, or PHA. Bacteria accumulate PHA in the presence of excess carbon source. Poly 3-hydroxy butyric acid (PHB) is the most common microbial PHA. The main process involved  in making the biopolymers are detailed below:

Fermentation:

There are two ways fermentation can be used to create biopolymers and bioplastics: 

• Lactic Acid Fermentation- In this process, after the lactic acid is produced, it is converted to polylactic acid using traditional polymerization processes.

• Bacterial Polyester Fermentation –It is the process by which bacteria can be used to create polyesters. Bacteria called Ralstonia eutropha, Ralstonia eutropha, Bacillus megaterium, Ralstonia spp., Pseudomonas putida, Pseudomonas spp., Bacillus mycoides, Alcanivorax borkumensi, Rhodococcus ruber etc or other suitable bacterial species use the sugar of harvested plants, such as corn, to fuel their cellular processes. The by-product of these cellular processes is the polymer. The polymers are then separated from the bacterial cells.

Market size and Economics: 

Due to the fragmentation in the market it is difficult to estimate the total market size for bioplastics, but estimates put global consumption in 2006 at around 85,000 tonnes.  In contrast, global consumption of all flexible packaging is estimated at around 12.3 million tonnes.

COPA (Committee of Agricultural Organisation in the European Union) and COGEGA (General Committee for the Agricultural Cooperation in the European Union) have made an assessment of the potential of bioplastics in different sectors of the European economy:

The European Bioplastics trade group predicted annual capacity would more than triple to 1.5 million tons by 2011. BCC Research forecasts the global market for biodegradable polymers to grow at a compound average growth rate of more than 17 percent through 2012. Even so, bioplastics will encompass a small niche of the overall plastic market, which is forecast to reach 500 billion pounds (220 million tonnes) globally by 2010.

Cost

With the exception of cellulose, most bioplastic technology is relatively new and is currently not cost competitive with (petroplastics). Bioplastics do not reach the fossil fuel parity on fossil fuel-derived energy for their manufacturing, reducing the cost advantage over petroleum-based plastic.

Advantages

• Biodegradable
• Eco-friendly synthesis
• High processibility
• Derived from renewable resources
• Good mechanical properties

Disadvantages

Despite the fact that bioplastics are a great improvement over fossil-based fuels, they are not yet the perfect solution. Here’s why:

• Most recycling centers are not set up to handle large      amounts of PLA. Presently, PLA products cannot be recycled in conjunction      with petroleum-based products, which means sorting is critical.
• Bioplastics are "compostable," but only under      specific conditions
• Plant-based bioplastics have a low melting point. This      means that if you leave a corn-based take-away container in your car on a      warm day, when you return you might find that it has melted into a small      puddle.
•  Poor interactions with fibers
• Narrow processing  window
• Lack of reactive  groups
•  Thermal degradation
• Brittleness

Companies:

  This is a list of companies that produce bioplastics.

• BASF
• Innovia Films
• NatureWorks LLC
• CSM
• Toyota and Nokia  have also opted for bioplastics for their future products.
• Metabolix, Mitsubishi Inc, Kaneka and Biomer are significant names in the high tech  PHA/PHB category of biodegradable plastics.

Recent developments:

• 2004-  NEC developed a flame retardant plastic, polylactic acid, without using toxic chemicals such as halogensand phosphorus compounds
• 2005- Fujitsu became one of the first technology companies to make personal computer cases from bioplastics
• 2007 - Braskem of Brazil announced it had developed a route to manufacture high density polyethylene (HDPE) using ethylene derived from sugar cane.
• 2008- A University of Warwick team created a soap free emulsion polymerization process which makes colloid particles of polymer dispersed in water and in a one step process adds nanometre sized silica-based particles to the mix.

Current research:

• Bioplastics can be genetically engineered from Pseudomonas by the mutation of some of the genes involved in the β-oxidation pathway.

• A new protein immobilization and purification system has been developed based on the use of polyhydroxyalkanoates. The N-terminal domain of the PhaF phasin (a PHA-granule-associated protein) from Pseudomonas putida GPo1 was used as a polypeptide tag (BioF) to anchor fusion proteins to PHAs. This tag provides a novel way to immobilize proteins in vivo by using bioplastics as supports. The efficiency of this system has been demonstrated by constructing two BioF fusion products, including a functional BioF-ß-galactosidase. This is the first example of an active bioplastic consisting of a biodegradable matrix carrying an active enzyme.
• Renewable Resource-Based Green Composites were successfully fabricated from Recycled Cellulose Fiber and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Bioplastic by melt mixing technique.
• Renewable resource based green composites were prepared from wood fiber and a bacterial polyester i.e., polyhydroxybutyrate-co-valerate (PHBV) via extrusion–injection molding process.