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BASF touts GM spuds for starch


29 November 2006

German chemical giant BASF is awaiting EU approval for commercial cultivation of one of its latest breakthroughs, an inedible potato called Amflora. Unappealing as it sounds, the GM spud will make a key contribution to renewable resources across Europe, says Thorsten Storck, global project manager at BASF Plant Science. The crop has been modified to produce a type of starch particularly suited to paper production.

The company claims that Amflora starch will have economic and environmental advantages over standard potato starch, which contains a mixture of 80 per cent amylopectin and 20 per cent amylose. Both these compounds are glucose polymers, but they have very different physicochemical characteristics. 

Amylopectin has an extensively branched structure, and is a thickening agent. Amylose has a more linear, unbranched structure, and is a gelling agent. Gelation interferes with several industrial applications of starch, leaving producers with a lumpy mess. To reduce the tendency of amylose to gel, starch has to be chemically modified before use - a process involving both energy and water.

BASF researchers say they have the solution. They have modified one of the potato's genes for starch synthesis (which encodes an enzyme called granule-bound starch synthase, or GBSS) and report that the resulting potato produces 100 per cent amylopectin.

There is no method to synthesise starch commercially, so starch is derived principally from corn, but also from potatoes and cassava. There has been a type of corn that produces only amylopectin for over 100 years, but corn is less well suited to the northern European climate and is often imported.

Persuading potatoes to make amylopectin-rich starch has proved more of a challenge. Potatoes have the advantage not only of being suitable for cultivation in northern Europe, but also of producing starch that is better suited to certain industrial processes used to make paper, textiles, adhesives and packaging. 

A potato that produces only amylopectin was developed in the Netherlands over ten years ago, and several other companies are working hard to release their own GM varieties. While BASF cannot claim Amflora as a great scientific first, say experts working in the field, they are to be congratulated for getting their potato this close to approval for cultivation in the European Union. The weight behind arguably the largest chemical company in the world has played an essential role.

'This is a very interesting step in the development of renewable industrial materials,' said Alison Smith, head of the department of metabolic biology at the John Innes Centre, Norwich, UK. 

The company hopes to gain EU approval following discussions in December, and plans to begin cultivation next year. This will be the first time in eight years that the EU has debated the approval of a live genetically modified organism (GMO).

The fact that this is a non-food crop may work in its favour, and will be an important test case, being the first GMO to go up before regulatory authorities since a de facto EU moratorium on biotech approvals was lifted in 2004.

Bea Perks

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