The "PlantBottle™" is currently made through an innovative process that turns sugar cane and molasses, a by-product of sugar production, into a key component for PET plastic.
This is ironic in that Coke uses high-fructose corn syrup as the sweetener in its beverages. This is generally the result of price supports for sugar and subsidies to the corn industry.
It should also be noted that in Florida much of the sugar cane waste is burned along with yard waste from places such as South Florida for energy.
While this may not be "the answer", Coke should be commended for trying something new. This bottle reuses waste, and decreases our dependence on foreign oil. Let's hope for a 100% waste-based bottle in the future that is also compostable.