You're welcome, Bhavika. About the other question:
"Chitin and chitosan are copolymers build from N-acetyl-D-glucosamine and D-glucosamine. The former is widely found in nature and yields the latter on deacetylation. The copolymers are being used for several purposes. Since 1977, when the First International Conference on Chitin and Chitosan was held in Boston, USA, the interest on chitin and chitosan has remarkably increased. This review emphasizes pharmaceutical applications of chitosan and its derivatives, and presents recent advances. Some therapeutical applications of these polymers are also discussed." http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422006000400026
Shortly, some animals such as shrimp and crab have it on their shell. It is derived from chitin. Some other applications of chitosan are used as edible coating, color absorbent, and as chelating agent. In my country, the use of chitosan that mixed with other materials successfully produce biodegradable plastic.
Depending on the biological source properties of some bio plastics can be tuned to the same properties as plastics based on crude oil or gas. Technically it is nothing very special.
There are only two things, which are difficult with bioplastics:
1. They are around factor 4 more expensive than standard plastics
2. The ecological aspect is not really clear. There are a lot of questions regarding water and agricultural land consumption, where bioplastics are worse than plastics made from oil or gas.
The company BAYER in Germany has also started to work on plastics made out of CO2.
Bioplastics are just used actually in special areas, where either just by (mostly government funded) developments, special properties for low production volumes achieved, where the standard plastic producer put no effort in or where some big companies (e.g. Coca Cola, DANONE, Nestle) advertise "green package" and this advertisement is for these companies sometimes worth spending more money for the raw material.
In countries like Brazil, where we have enough land to grow plants for producing plastics and on the other hand, the chemical industry is anyhow by far to small to fulfill the local need of plastics, I can imagine that mid term it could also make sense from a business perspective.
For most areas (especially Europe or US) I do not believe, that beside the "political" and "advertisement" effect, which has no proven overall ecological advantage, it makes a lot of sense, beside some niche applications. But this is my personal opinion.