INDONESIA SPICES

Sago, an interesting but underutilized ethanol crop

The true sago palm, Metroxylon sagu, has been described as mankind's oldest food plant with the starch contained in the trunk used as a staple food in southeast Asia. Traditionally, hunter-gatherers use a complex and labor-intensive process of felling the tree, splitting it open, removing the starch and cleaning out its poisonous substances, after which it is ready to be consumed. The starch itself is very nutritious and some of us may have even tasted it because tapioca flour is made from it.
As these sago-growing hunter-gatherers migrate to the cities, they abandon their healthy starch-rich diet and choose for fat and sugar food habits that don't differ much from ours.

But the sago palm remains, in the wild. The International Plant Genetic Resources Institute (IPGRI), which strives towards diversifying the world's agricultural crop base and maximizing the potential of less known plant species, considers the palm to be a typical "underutilized" crop. It published an easily accessible but comprehensive study about sago[*.pdf], in its series about "neglected and underutilized species". The study shows the potential of the crop, where and how it is currently used, which barriers there are to increasing its use, and which environmental problems could be associated with its cultivation.

One of the potential uses of the sago palm is ethanol. Throughout its lifecyle, the tree accumulates vast amounts of starch, reaching a maximum when it is about 15 years old, right before its (single) inflorescence occurs. In the wild, around 5 tonnes of starch per hectare can be harvested, but plantations show starch yields of up to 30 tonnes per year.

More importantly, the starch is of such a quality that ethanol conversion efficiencies of up to 72% can be obtained (for hydrated ethanol). Taking an optimistic yield of 20 tons of clean starch per hectare, this comes down to an alcohol yield of 14,400 litres, (1540 gallons per acre) making sago one of the most productive energy crops.

But this is theory. Contrary to palm oil, soya, coconut, cassava and most other tropical crops, sago suffers under a lack of research and development, most notably in crop improvement, phytopathology and plantation management techniques. Despite yearly symposia on sago, the palm has a long way to go before it will be used on a large scale.

Here and there, things are moving, though. The Malaysian government has started a 50,000 hectare plantation with sago palms in Sarawak, and considers it to be a crop with large potential for the development of a biofuels industry. Sago is set to become the second pillar [*.pdf] of Malaysia's bioenergy program.


This is just an introductory file which we will be updating regularly. Here at the BioPact we try to broaden the debate about biofuels, and we try to introduce underutilized crops into it.