Some biopolymers- such as  PLA, naturally occurring zein, and poly-3-hydroxybutyrate can be used as plastics, replacing the need for polystyrene or polyethylene based plastics.
Some plastics are now referred to as being degradable, oxy-degradable or UV-degradable. This means that they break down when exposed to light or air, but these plastics are still primarily (as much as 98 per cent) oil-based and are not currently certified as biodegradable under the European Union directive on Packaging and Packaging Waste (94/62/EC). Biopolymers will break down, and some are suitable for domestic composting.
Biopolymers (also called renewable polymers) are produced from biomass for use in the packaging industry. Biomass comes from crops such as sugar beet, potatoes, or wheat: when used to produce biopolymers, these are classified as non food crops. These can be converted in the following pathways:
Sugar beet &gt; Glyconic acid &gt; Polyglyconic acid
Starch &gt; (fermentation) &gt; Lactic acid &gt; Polylactic acid (PLA)
Biomass &gt; (fermentation) &gt; Bioethanol &gt; Ethene &gt; Polyethylene
Many types of packaging can be made from biopolymers: food trays, blown starch pellets for shipping fragile goods, thin films for wrapping.