As others have said, you can't go wrong with Nylon (http://www.amazon.com/gp/product/B00BGWRYIW).

Or if you're feeling adventurous, give PLA+PHA a try. It's supposed to be stronger than PLA alone (more flexibility) but still uses the same temps as PLA and is biodegradable still.

http://www.amazon.com/gp/product/B010L13CHU