Bio Bottle made from Corn

Belu mineral water have started packaging their product in a compostable bottle made from corn. The lid still has to be recycled with other plastic products.

Another clever environmentally-friendly aspect of this company is that their water is sourced in the UK and sold in the UK thereby reducing transport pollution and costs.

There's a wee something in me that isn't convinced! The "composting" page on the website details temperature / humidity and other conditions that are required to compost the bottle. So how bio-degradable is it? What happens in a landfill? I'm just being a bit cynical - I do think it's a good start to the idea of using other materials than plastic. The Q&A part of the website says this much:
Q: What are bio-bottles made of?
A: Bio-bottles are made from corn but could equally well be made from potatoes, rice, beetroot, bio-mass or pretty much any carbohydrate or sugar. The corn goes through a fermentation and distillation process similar to making corn whisky and is reduced to a monomer called lactic acid (which you can also find in ice cream and pickles). This lactic acid is then spun, linked into polymer chains and moulded into bottles.

http://www.belu.org/