From 2012 to 2017 the global annual production capacity of bioplastics will increase from 1.4 million tonnes to more than 6 million (1). This staggering increase is driven by many factors, the most relevant being both the availability and renewability of biomass. High consumer acceptance of renewable bioplastics makes them an attractive choice compared to fossil materials which are made from finite oil resources.
Bioplastics typically require a carbohydrate source for production. Carbohydrates can be fermented to produce the basic units (monomers) for further processing to make bioplastic. In the case of polylactic acid (PLA, the leading biodegradable and biobased plastic) corn starch is converted to dextrose which is then fermented to make lactic acid. The lactic acid is then converted to lactides for polymerisation to high performance polylactic acid.
The increasing volumes of bioplastic production have led to a debate about using potential foodstuffs (corn, sugar) to make plastic. In fact, Floreon has been asked on a few occasions; Floreon is a corn-based material, is this using potential foodstuff out of the food chain that could be used to feed starving children?
Our short answer to this is no. Growing food, feed and using pastures accounts for about 97 percent of the global agricultural area, biomass grown for material use only counts for approximately 2 percent, of this 2 percent - bioplastics account for less than 0.01 percent, and even to satisfy the predicted demand for 2017 this will only rise to around 0.02 percent (2). This difference in volume shows just how little biomass is used for material use and how it will have no effect on food and feed.
Looking to the future, a more diverse range of feedstocks are in development. Corn is currently the main carbohydrate source for PLA production since it is economical and abundant, but several new generations of feedstock are in development. In the short term, this will be diversified to other locally abundant sources such as sugar cane or sugar beet. Beyond this, second generation lignocellulosic feedstocks such as straw and waste biomass will be utilised. For the distant future, the agricultural step may be completely cut out as new technologies are developed to convert carbon dioxide or methane directly to lactic acid.
Further information on feedstocks for PLA can be found on the Natureworks website (3).
(3) http://www.natureworksllc.com/The-Ingeo-Journey/Raw-Materials#feedstocks← Return to Article Archives