Jim Kleinschmidt, Director, Rural Communities Program, IATP (USA) explained that the Institute for Agriculture and Trade Policy worked at the intersection of policy and practice to ensure fair and sustainable food, farm and trading systems for all. Their Sustainable Biomaterials Collaborative promoted cradle-cradle thinking in developing sustainability guidelines by engaging markets and policy makers.
In the USA, corn is the primary source of biopolymers. A bushel (~60lbs) of corn can be used to make 32lbs of starch or sweeteners, or 2.8 gallons of ethanol, or 22.4 lbs of PLA. In 2010-11, 40% of US corn went into ethanol (39% fuel + 1% beverage alcohol), 39% into animal feed, 14% was exported, and the rest went into food products and seed.
In 2010 the global production biopolymers (natural biopolymers being excluded) amounted to 724,000 tonnes of which 112,000 tonnes were PLA made from the starch from less than 0.1% of the US crop. To grow corn, 133-155kgs of nitrogen fertiliser are needed per hectare, and production of this is fossil-fuel intensive. Corn is also among the highest users of pesticides and irrigation water, and requires proprietary hybrid seeds for best results. 88% of corn and 94% of soya (which alternates with corn on many farms) were genetically modified in 2011.
In addition to the popular concerns about GMOs, their negative effects on biodiversity, pollinating insects (especially the Monarch butterfly), and the evolution of super-weeds (more herbicides needed) are becoming important. In short, the economic benefits of GMO’s are diminishing.
Corn production specifically for bioplastics, where new varieties and techniques of farming might become more acceptable, is only just commencing. The Working Landscapes Initiative is now supporting family farms to move to more sustainable practices for biopolymer feedstock production. In 2010 Stonyfield Farm (packaging) became the first to adopt WLI methods and Certification for making yogurt pots via PLA production. In 2012, about 2000 acres will be planted and harvested to WLI standards and this will feed Danone (Germany) with enough PLA for a million yogurt pots. The WLI is seen to be the start of a movement towards farming perennial biomass for polymers.
Today’s biopolymer feedstocks (sugar cane, corn, wheat and potatoes) will be unacceptable in future due to competition with food requirements. To grow sustainably, the industry must switch to non-food biomass such as forest residues, grasses, bamboo and leaves – i.e. to cellulose rather than starch.
Could corn-crop residues be used as biomass for polymer production? In principle, yes, but soil erosion would be a problem if the soil were to be stripped of its stubbly winter protection.
(from a paper given at the Biopolymer World Conference, Venice, April 2012)