Maple Syrup for Packaging

Maple trees, long treasured for their delicious maple syrup to pour over our pancakes, is now being tapped for a new use. Researchers have discovered that the sap can be used as a base for a natural, biodegradable polymer that could help us take another small step away from our dependence on fossil fuel-based plastics.

A range of new biodegradable products will be possible, such as packaging material, and medical applications like drug delivery systems and surgical sutures, the National Research Council said.

Canadian producers accounted for 86% - over 34,000 tons - of the world's maple syrup production last year, with the United States accounting for the remainder. This production led to sales of $178 million in 2006, according to Agriculture and Agri-Food Canada.

After reading a report in a Quebec newspaper about a 27 million kilogram surplus of maple sap, due to slipping domestic sales, NRC scientist Jalal Hawari decided to see if the substance might help him with a project he was working on to create natural polymers. Hawari said the secret behind this new technology is bacteria called Alcaligenes latus, known for transforming sucrose into a group of naturally occurring polymers called polyhydroxyalkannoates, or PHAs. Before turning to maple sap, Hawari's group had been feeding the bacteria liquid waste from the apple juice manufacturing process.

The bacteria find the syrup an excellent food source. While the bacteria feed on the sap, they process the sugars and store much of what they cannot eat in the form of PHAs, which can then be extracted and used as a biodegradable material. This is done much more efficiently in maple sap than in other sucrose solutions. While corn and sugar cane can be used in a similar manner to feed the bacteria, Hawari said breaking them down into a sugary solution palatable to the bacteria adds to the cost.

Unlike fossil fuel-based polymers, natural polymers biodegrade over time more readily, but are still stable enough to perform their functions. They are also biologically inert, meaning they won't adversely affect humans if used for medical applications or wild animals who will ingest the substances once they are thrown away.

Since currently only one-third of the potential reserves of maple trees are tapped, using this food source for other than food purposes may not increase the retail price of syrup, unlike what has happened in using corn for ethanol.