March 17, 2009
Palm oil waste and fly maggots seen as potential fish feed
The synergy of palm oil refinery waste and fly maggots could produce a low-cost feed for farmed fish, while reducing a source of pollution, according to the Institute for Research and Development (IRD) in the southern French port of Marseille.
The process can recycle palm oil refinery waste and convert it into cheap fish feed and 'green' fertiliser, said IRD researcher Saurin Hem.
The IRD has developed the technique with partners from Indonesia, which produces nearly 2.3 million tonnes of palm oil per year.
Jakarta is set to start using the method this year at a refinery on the western island of Sumatra, IRD said.
Palm oil production generates million of tonnes of palm kernel meal that can pollute the environment. Some palm kernel meal is exported to Australia, Europe and the US as cattle feed, but most of it is left to rot.
When feed trials involving palm kernel meal and tilapia failed, IRD scientists dumped the fermented mixture which rotted in two weeks' time but attracted the attention of chickens and other birds.
A species called black solider flies had been attracted by the rotting smell and laid eggs on the refuse.
The IRD scientists then concluded that enzymes secreted by the fly larvae had changed the chemistry of the fermenting mixture. When fed to the tilapia, the fish grew 3.5-times faster than with previous feeds, and gained three times as much weight per day.